The sexual organs are not the only defining parts of a male’s body and in the case of ‘trans-men’ and‘ non-binary’, the genitals are not representative of the gender of the person.
Male anatomy is a term used to refer to the parts of the human body that belong solely to males, rather than to both males and females. The male reproductive organs, for example, are considered male anatomy, but the heart and lungs are usually not.
There are differences that we all have in human anatomy; Cis-Men (assigned male sex at birth) possess external genitalia (the penis, scrotum and testes) for the production and delivery of sperm, and Cis-Women (assigned female sex at birth) possess internal genitalia (the vagina, uterus and ovaries) for the production of eggs and the development of human embryos. Most physiological differences between men and women occur due to differences in the endocrine systems during critical periods of development, such as foetal growth and puberty.
The functions of the endocrine systems in men and women lead to other physiological differences throughout life. For example, men produce a more course and visible type of hair follicle called terminal hairs on the chest, abdomen, face and back. Women, however, produce a finer hair follicle called vellus hairs in fewer areas of the body. Hormone production in the endocrine system is also partially responsible for the development and differences of pattern baldness in men and women.
Great differences are also present in the skeletal and muscular systems in men and women. Typically, men possess denser, stronger tendons, ligaments, and bones than women, and men generally have more muscle mass. This leads to differences in physical strength and the metabolic processes of calorie expenditure and storage. In comparison, women typically possess a skeletal system that is less robust and smoother in structure than that found in males.
Studies that have looked at the anatomical differences in the brains of males and females have focused on:
Total brain size
In adults, the average brain weight in men is about 11-12% MORE than the average brain weight in women. This does not suggest that due to the larger brain males are smarter than females.
It is reported that a woman’s brain has a larger corpus colosseum, a tissue that separates the right hemisphere from the left hemisphere, which means women can transfer data between these 2 halves of the brain faster than men.
Two areas in the frontal and temporal lobes related to language are significantly larger in women, thus providing a biological reason for women’s notorious superiority in language-associated thoughts and verbal expressions.
Inferior parietal lobule (IPL)
It is a brain region in the cortex, which is significantly larger in men than in women. This is the same area which was shown to be larger in the brain of Albert Einstein, as well as in other physicists and mathematicians. It seems that IPL’s size correlates highly with mental mathematical abilities. Studies have linked the right IPL with the memory involved in understanding and manipulating spatial relationships and the ability to sense relationships between body parts. It is also related to the perception of our own affects or feelings. Moreover, the left IPL is involved with perception of time and speed, and the ability to mentally rotate 3-D figures.
Males on average, have a smaller limbic system than women, and as a result, women are more in touch with their feelings; they are generally more able to express their feelings than men. They have an increased ability to bond and be connected to others.
Many behavioural differences have been reported for men and women. These differences appear in the way men and women:
· Estimate the time
· Judge speed of things
· Carry out mental mathematical calculations
· Orient in space
· Visualize objects in three dimensions
· Process language
· Express their emotions
· Show affection verbally and non-verbally
Socio-biologist, Edward O. Wilson, said that human females tend to be higher than males in empathy, verbal skills, social skills, and security seeking, among other things, while men tend to be higher in independence, dominance, spatial and mathematical skills, rank-related aggression, and other characteristics. This may account, scientists say, for the fact that there are many more male mathematicians, airplane pilots and race car drivers than female ones.
Tests show that women generally can recall lists of words or paragraphs of text better than men. On the other hand, men usually perform better on tests that require the ability to mentally rotate an image to solve a problem.
Mental rotation is thought to help people find their way. This in no way reflects on women’s abilities in the same area, they are just different. Scientists believe that women may rely on their memory and recall landmarks to find a destination that is men are more likely to navigate by estimating distance in space and orientation, whereas women are more likely to navigate by monitoring landmarks.
Male Development In The Womb
One of the most exciting things about having a child is learning the gender of the baby. Many people choose to find out as soon as possible, while others decide to keep it a surprise. Although you may not see sex organs on a sonogram for weeks, a baby’s sex is determined long before it arrives in the world.
Gender is determined immediately upon fertilization. The 23rd pair of chromosomes establishes the sex of the baby. The mother’s egg contains an X chromosome, while the father’s sperm carries either another X or a Y chromosome. An XX combination means your baby is female, and an XY combination means your baby is male. This means that the baby’s gender is determined before it is even considered a foetus. Other chromosomal diversities can differ the gender of the baby and this is discussed further in the Intersex section.
Though during the first few weeks of foetal development your baby’s internal and external genital structures are the same, the organs will eventually change. Your baby’s gonads will either become ovaries or testicles. The phallus will become either a clitoris or a penis, and the genital folds will become either labia or scrotum. This all depends whether or not testosterone is present. Testosterone will be present in embryos with a Y chromosome, and male sex organs will begin to form. If testosterone is not present, female organs will develop, making female the “default sex” for human beings. There are also other influences at this stage of development that can result in the baby being intersex and this is discussed further in the ‘Intersex’ sections.
Sex Organs Are Visible:
Although your baby’s gender is determined immediately upon fertilization, you will not be able to know the sex until about the 16th to 18th week of pregnancy. At around the sixth week your baby will develop a small bud called the genital tuber at the site of the genitals. This will look the same for boys and girls until around the 9th week when the sex organs begin to form. By the end of the 20th week, the external sex organs should be fully formed for both male and female babies. In some instances, the baby may be born with both male and female sex organs and may result in the early identification of the gender being incorrect.
According to the Intersex Society of North America (ISNA), “intersex” is a term used to describe a variety of conditions in which a person is born with a sexual anatomy that doesn’t fit typical definitions of male or female. For instance, a person may be born with genitals that are in-between the usual male and female parts or may be born with both XX and XY chromosomes. The ISNA says, to understand intersex, think of gender like the colour spectrum. Sex organs vary in shape and size, and sex chromosomes can vary as well. While most cultures divide people into male and female categories, this is not the way of nature. This condition is very rare, but it does exist.
Gender as a Controversial Issue:
The word “gender” has become quite controversial. Some say gender is biological, while others say gender is purely a product of the child’s environment. In other words, if you put a child in a pink room and teach, he or she to play with dolls, that baby will identify as a girl. If you put a child in a blue room and teach him or her to play with cars or trucks, he or she will identify as boy. Although socialization does impact on all humans, biologically people are born with a gender-brain. In earlier times, the gender of intersex babies was determined by the parents' choice of gender, however as the child developed their thoughts and behaviour didn’t always compliment their genitalia, or their social influences. By age 2 or 3, your baby will begin to develop an awareness of being either male or female and begin to act accordingly. For the child who is Intersex, the non-conformity between genitalia, social expectations, and how they feel and identify as individuals, can cause severe disruption in their future development. A person may not have external or behavioural gender differences but have internal gender variances. Biologically, ‘gender’ does not always correspond with the simplistic definition of ‘male or female’ that our society has based its structures on.
The information above has been adapted from:
Dave Wells works with people, without the use of labels, and with the aim of discovering the individual that you are, inclusive of all your diversities. Regardless of legal, and biological gender identification, client’s gender is identified by their feelings of preference, and/or how they wish to present, which can fit within the male/female stereotypes, or alternatively.
The Male Body
Traditionally, the male body has been identified as being inclusive of a penis and testicles. As explained in the diverse-gender section of my website, an individual may have a male-gendered brain, but their body contains the sexual organs of female breasts and a vagina. In this section, the male body will be focused on from the cis-male body’ perspective.
The sexual organs are not the only defining parts of a male’s body.
There are many different systems for classifying male body types. Classification models attempt to describe not only how different body types appear, but also how they’re able to gain, maintain, and lose weight. This is useful information for dietitians and workout trainers, who often use body type models to assess how a client should change a diet and exercise routine. Body type models can also be useful to individuals interested in better understanding how their body works.
Some basic types used include ectomorph, mesomorph, and endomorph.
The Endomorph male body types are the naturally largest. These body types tend to be more rotund, with generous amounts of muscle weight and fatty weight. Endomorph types typically have the slowest metabolism, and therefore have the most difficult time shedding weight. Males with this body type often find that they’re easily able to gain muscle mass with weight-lifting routine, although it’s often necessary to focus just as much on cardio exercises to trim fatty weight.
The Mesomorph types respond the best to muscle-building exercises. They’re typically better able to gain and shed muscle mass than other body types. Having an easier time at gaining muscle mass has its downsides though — mesomorph types are also more inclined than ectomorph types to gain fat. This means that, with the right workout routine and diet, mesomorphs are the most naturally inclined for weightlifting success. Without careful regulation, however, a mesomorph might be prone to gaining too much fatty weight.
The Ectomorph male body types are lanky and skinny physiques that don’t contain a lot of muscle mass or fat. Such males often have a faster metabolism than other body types, meaning that their bodies naturally burn fat and calories at a higher rate. This makes it difficult for ectomorph body types to gain weight and muscle mass, even with rigorous dieting and workout routines.
It’s common for males to have a combination of body types. Ectomorph-mesomorph, as well as mesomorph-endomorph are frequent combinations of male body types. Understanding one’s own body type can be helpful in deciding what workout routine to adopt, as well as what supplements and eating habits to implement into a diet.
There are many other body type classification systems that use different terms to describe the same basic body types. One such system divides male body types into letters, such as type A, G, P, and T. This model uses four body types as opposed to three, which is just another way of looking at and dividing up the ecto-, meso- and endomorph models.
Some aspects of body shape and size are more closely related to genes than other influences.
The ease that a person develops muscle mass is a highly inherited trait, it is also believed that inherited genes can be responsible for men storing extra weight in the stomach areas.
Studies suggest that while your genes may determine up to 80% of your body weight and body shape, environmental and personal choices still play a significant role.
Societal impact on body weight and shape
Regardless of your bodyweight and body shape and the reasons for it, we all can achieve the body that we are comfortable with, and although exercise and diet are important, your psychological view of yourself is paramount.
Unfortunately, we live in a society that views and perpetrates that the only desirable body shape and body weight is muscular and big if you are a male, and thin and petite if you are a woman. A more important issue is that people believe that they have the right to comment on another person’s body! Have you lost weight, or have you put on weight? Fatty, skinny.
Teasing and judgement from an early age can have dire consequences on a person’s self-esteem and self-confidence throughout their lives, and especially their self-worth. This can affect their relationships, their employment/study, mental health, in fact every area of their life. The longer a person believes the negative comments about their body and shape and size, the more difficult to change their perceptions of themselves.
Many will continually try to change their body with dieting, weightlifting, exercise, health supplements, etc. Although exercising and a healthy diet is essential for your over-all health, true acceptance of your body creates the greatest gains.
A lifetime of not accepting your body and negative messaging related to it, can be changed but it is not a quick fix.
Body dysmorphia disorder is a mental illness involving obsessive focus on a perceived flaw in appearance. The flaw maybe minor, or even imagined, but it will translate to the person spending a disproportionate amount of time trying to fix it. For example, the person might diet or exercise to excess or over-do cosmetic procedures. The person with this disorder may frequently examine their appearance in a mirror and constantly compare themselves to others.
Dave Wells believes that the human body in all of its shapes, sizes, and, abilities is a work of art. Of course, when a person hates or is disillusioned with their body, seeing it from this perspective can be impossible, however it is possible to change a person’s mind set towards self-acceptance and create positive change.
Not all people who dislike their body are at a stage of body dysmorphia disorder, it is often a term that is thrown around to label a person who does not accept their body or parts of their body. For those people who are at the extreme end of the body dysmorphic spectrum, anti-depressants combined with therapy may be required to improve the persons thought processes. For others, ‘integrated’ and ‘eclectic’ therapy approaches blend the different counselling models, and particular therapeutic approaches, to support the individual through to recovery where they hold a healthier view of themselves and have a greater resiliency to any ignorant comments made by others.
Although work is always being done to change the attitudes held in our society they will always exist. The only real change that can be made is to hold a healthy view of ourselves.
Parts of a Males Sexual Anatomy
The penis is a man’s reproductive and sex organ. It is formed of three columns of spongy tissue — the corpus spongiosum and two corpora cavernosa — that fill with blood during sexual excitement, causing an erection (“hard on”). The penis extends from the lower portion of the belly. It is made up of a shaft and a glans (also known as the head) and is very sensitive to the touch. A man’s urethra is enclosed in his penis. It carries urine, pre-ejaculate, and semen out of his body.
The shaft looks like a tube. The shaft of the penis is about 1–3 inches long when soft. During an erection, the shaft expands to generally reach 4–6 inches.
Corpora Cavernosa (two spongy cylinders on either side of the penis)
These fill with blood to make the cock erect. It stay’s erect as the blood is trapped within it – you can also keep these spongy bodies filled by using a cock-ring which traps the blood so you don’t lose an erection.
They are two spongy bodies of erectile tissue on either side of the top of the penis, which fill with blood and make it erect. The blood is temporarily trapped in there by the tightening of blood vessels that would normally allow it out.
None, most of the nerves are in the head & foreskin. If you need to use Caverject (ED injectable medication) any pain is extremely minimal.
HIV transmission role:
Corpus Spongiosum (cylindrical erectile tissue at the base of your penis shaft)
·Erectile tissue through which the urethra passes
Runs along the base of the penis. It thickens and forms a ‘root’ or ‘bulb’ that is attached to a thick fibrous membrane which gives it stability and is surrounded by a pelvic floor muscle (Bulbospongiosus) that contracts rhythmically during cumming. At the other end it grows to form the glans. It contains erectile tissue that swells in a similar manner to the Corpora Cavernosa during erection, although it does not become as enlarged as it contains more fibrous tissue and has less spaces to fill. Unlike the Corpora Cavernosa it maintains a blood supply during erection.
The urethra responds to being rubbed and this is one of the best places to rub it.
HIV transmission role:
Gently rubbing your fingertips or the side of your thumb along the ridge of his corona - great feeling.
Root of penis
Anchors the penis deep in the body.
When you’ve got an erection, the engorgement of the root helps stop the flow of urine from your bladder.
Bulb-like end of your penis.
Only a proportion of your penis root is actually visible.
Supplied with nerve endings responsive to pressure, so responds well to being rubbed externally and internally.
HIV transmission role:
Apply gentle rubbing pressure to his erection right at the base – the point at where his penis meets his sphincters.
Insert a well-lubed finger into his anus and just inside towards the front try massaging the base of his cock through the wall.
The glans is the soft and highly sensitive Head (knob) of the penis
Corona (the ridge around the glans):
· Its shape puts thenerves that give you pleasure in the best place to be stimulated, while at thesame time being useful for pleasuring a partner.
· Will usually have benign bumps called ‘pearly penile papules’ attached to it.
· It contains nerve endings which transmit pleasurable sensations from stroking & vibration, but they don’t respond at all to steady pressure.
· The whole of the glans including the corona, is a mucous membrane and have the absorption properties necessary for exposure and transmission.
· Gently rubbing your fingertips or the side of your thumb along the ridge of his corona – brings pleasure.
Opening of the Urethra:
The opening of the urethra is located at the tip of the penis. This is where pre-ejaculate, semen, and urine leave the body.
Some men enjoy a sexual activity called ‘sounding’. ‘Sounding’ is where a person inserts a rod/needle-type object down the eye of the urethra, which brings a heightened sensation when orgasming.
The urethra can be an entry point for HIV transmission, especially if damaged. The whole of the glans including the corona, is a mucous membrane and have the absorption properties necessary for exposure and transmission.
The foreskin is a retractable tube of skin that covers and protects the head (glans). Some men have had their foreskin removed by circumcision during infancy. Some choose or need to be circumcised later in life.
Stores pheromones & releases them when you are erect. It also stores & releases natural lubricants, which mix with dead skin cells to make smegma. The inner surface is a mucous membrane.
Has the most nerve endings in the penis, more even than the glans. A ridged band of skin and a group of skin/nerve cells (Meissner’s corpuscles) are sensitive to vibration & touch and send pleasure signals in a similar way to those in your fingertips.
The interior of the foreskin is a mucous membrane and has the absorption qualities necessary for HIV exposure and transmission to occur.
The foreskin has many nerve endings so take some time to stroke, lick and play with the foreskin where it’s present.
The bulb-like ending of the Corpus Spongiosum. Smooth skinned, the glans is covered with a mucous membrane and deepens in colour as orgasm approaches.
The whole of the glans is a mucous membrane and have the absorption properties necessary for exposure and transmission.
As the Glans responds to being enclosed, you can hold it in the palm of your hand and close it gently over it, squeezing slowly. It also works well when it is receiving oral sex, clamping it with your tongue and the roof of your mouth.
The frenulum is where the foreskin attaches to the underside of the penis just below the glans. Usually, a portion of it remains after circumcision.
Underneath the glans, it stretches when the penis becomes erect and becomes highly sensitised.
Very sensitive when stretched during a hard on (it’s known to the French as the ‘sex nerve’) – it responds well to stroking & vibration.
The French call it the sex nerve for a reason; try flicking the tip of your tongue across the frenulum for those bonus sensations.
The scrotum is a sack of skin divided into two parts, enclosing the internal reproductive organs: the testicles. Its purpose is for holding the testicles outside the body to enable the best production of sperm (at 2 degrees lower than normal body temperature).
Basically, a pouch of skin hanging beneath the root of the penis contains the testicles. This skin is thin and usually darker than the other skin on the body. The scrotum contains smooth muscle fibres that contract in response to cold & exercise, drawing the balls closer to the body. This is a natural protective mechanism, but this also happens in the last stages of sex just as you are getting ready to orgasm.
The skin & muscle of the scrotum have a good supply of blood & nerves that respond well to touch, vibration & temperature changes.
None, unless the skin is broken and body fluid such as semen gets into the open wound. Be careful if you shave or pluck the hairs from your scrotum as any wounds can be a source of HIV transmission.
Lick and massage the scrotum with your mouth (without teeth) and where it joins onto the crutch.
Suck the scrotum and one testicle at a time, slightly pulling down. The warm sensation and slight pressure can be very stimulating. A good communication should be held with the person prior to ‘ball-play’ to ensure that they find it stimulating or else you risk turning the person right off sex.
Testicles have 2 main functions:
- They make male hormones (androgen’s) such as testosterone.
- They make sperm, the male cells needed to fertilize a female egg cell to start a pregnancy.
· The testicles are held in a pouch of skin hanging beneath the root of the penis called the scrotum (or ‘ball bag’).
· The testicles are oval shape, and it is not unusual for one to be larger than the other.
· Testicles continually rotate in the scrotum as a way of keeping the sperm at the right temperature.
· The testicles are joined to the seminal vesicle by the Vas Deferens. Where this joins is where lumps usually appear in a person who has testicular cancer. A regular check should explore the testicle where the vas deferens joins at the top.
· The testicles can be extremely sensitive and painful if knocked hard. However, some men find it extremely stimulating if their testicles are pulled and squeezed firmly, through too hard.
· Some men enjoy having their testicles sucked and licked (through the scrotum). A heat or cool sensation can be psychologically stimulating.
· None. (Asides from being involved in the process of making semen which does contain infectious quantities of HIV)
Seminiferous Tubules & Interstitial Tissue (tissue of your balls)
To produce sperm and testosterone
The Seminiferous Tubules are small hollow, fluid filled tubes filled with developing sperm cells that also produce a fluid that supplies the sperm with the nutrients & hormones they need to develop.
As well as the only blood and nerve supply in the balls, the Interstitial Tissue contains special cells (Leydig Cells) that produce testosterone.
None in the Seminiferous Tubules, but the Interstitial Tissue has very sensitive nerve endings that respond to pain, pressure, heat & cold.
To supply about 55% of the seminal fluid
Two finger length glands at the end of the Vas Deferens and next to/on top of the Prostate Gland that produce a fluid that is known as ‘sperm fuel’ as it activates the sperm and feeds it with fructose (a natural sugar).
During ejaculation, sperm cells are carried from the epididymis through the vas deferens to seminal vesicles, where they mix with fluids made by the vesicles, prostate gland, and other glands to form semen. This fluid then enters the urethra, the tube in the centre of the penis through which both urine and semen leave the body.
Sperm cells are made in long, thread-like tubes inside the testicles called seminiferous tubules. They are then stored in a small, coiled tube behind each testicle called the epididymis, where they mature.
Epididymis & Vas Deferens
To mature & carry the sperm to the Urethra.
The Epididymis is an extensively coiled tubular organ attached to the rear & side surface of the testis. Uncoiled it would be about 5-6 m (about 17ft) long. It takes about two weeks for the sperm to journey through the Epididymis maturing and learning to swim as they go.
· The Vas Deferens is a tube surrounded with smooth muscle that pumps the sperm from the tail of the Epididymis to the Urethra. There are two Vas Deferens. One from the right and one from the left testicle, both are about 40cms (18 inches) long.
To produce pre-cum, an alkaline fluid that prepares the urethra for semen. All men produce pre-cum (whether you know it or not) as an acidic environment can damage sperm – and urine can make the Urethra acidic.
· Two pea sized glands situated under the Prostate Gland that feed into the Urethra, producing about 5– 7% of the seminal fluid, usually known as pre-cum.
· The glands begin to produce fluid when you get sexually aroused.
Produces an alkaline fluid that neutralises acidic urethral and vaginal conditions.
Also squeezes shut the connection from the bladder to the Urethra to stop urine leaking into the semen.
Its main function is the production of fluids that are added to the seminal fluid (cum). It’s estimated that 40% of the fluid released when cumming comes from the Prostate Gland.
Usually described as a doughnut that surrounds the urethra, it is walnut sized in young men, getting bigger as you get older. This growth is dependent on the amount of testosterone you produce.
The Prostate Gland is normally rubbery, pliable, and smooth, and is made up of thousands of tiny fluid-producing glands interspersed within its blood vessels and muscular framework.
- From the outside:
The perineum is firmer near the front of the penile bulb, which is the inner ending of the shaft.
It feels softer and fleshier toward the back. This is the area you’re aiming for.
You may not be able to actually feel the gland but touching it will likely cause the sensation of needing to pee, but this feeling is also extremely stimulating.
From the inside:
· It feels like a fleshy bulb of tissue on the front wall of the rectal lining. It’ll feel different from the other tissue in there.
· The prostate is a walnut-sized gland located between the bladder and the penis. The prostate is located behind the anal wall in the direction of your belly button (two to four inches from the sphincter).
Some men can achieve orgasm through stimulation of the prostate gland, such as prostate massage or receptive anal intercourse, and men who report the sensation of prostate stimulation often give descriptions similar to females' accounts of G-spot stimulation. Prostate stimulation can produce a stronger, more powerful orgasm when rubbed.
It is possible for a man to reach orgasm through massaging the prostate, without having his penis touched. This is known as an internal orgasm, which many men describe as the ‘holy grail’ of male orgasms.
Techniques to try:
You will need to communicate with your partner and experiment with speed and pressure to find what feels best for him personally. Here are some techniques to try, whether you’re using fingers or toys.
With your fingers
Gently insert your lubed index finger into the anus and curl your finger upward in a “come here” motion toward the belly button. Keep repeating the motion while gradually increasing your speed as the pleasure builds.
Rest the pad of your finger against the outside of the prostate and gently press as you would to ring a doorbell. Mix it up by using different pressure or holding the press for shorter and longer intervals to find what works. You can use the doorbell technique when penetrating the anus, too.
Use the pad of your finger and run it all around the prostate, circling your way around the entire perimeter of the gland. Change up the pressure and speed and continue with the combo that feels best, allowing the pleasure to build up.
Any move that feels good can be sped up to the point of feeling like a vibrator. This can be a little hard on the wrist after a while, so it’s best to save this kind of speed for when orgasm is close.
With a massager, strap-on, or other sex toy
If you’re playing with sex toys, you can really mix it up by playing with the different types of toys such as a vibrator, dildo or you can get toys that are specifically designed to stimulate the prostate.
· Pressure: Controlling pressure when using a toy is easier, especially when you’re playing solo. Try pressing the toy against the prostate using more-or-less pressure till you find your sweet spot.
· Depth: Depth is another area where toys win out, since reaching can make it hard to go deep, if that’s what you crave. Try different sized anal toys or get a longer one that you can insert as deep as your bottom desires.
The information above has been adapted from: www.plannedparenthood.org/learn/sexuality/reproductive-sexual-anatomy
Essentially, men have nipples because nipples are part of the basic human design option at conception. While modern societies may view nipples as secondary sexual organs, in reality a foetus of either sex develops nipples within a few weeks of conception.
The human foetus actually develops several sets of nipples, much like other mammals, but only one set will fully mature in the womb. At this point in a foetuses 'development, there is no genetic difference between male or female. All foetuses develop nipples, chest muscles, and milk glands.
Nipples have the ability of being erogenous zones for men and work in the same was as they do for women. While male nipples are basically the same as female nipples, they can be even more sensitive since guys aren’t used to having them touched as often.
Men can find it extremely stimulating having their nipples pinched and sucked. It is always best to communicate first to discover what turns the person on, but if they inform you that they enjoy their nipples played with hard, then they will find this activity personally stimulating.
In most cases the more that a man’s nipples are played with the more resilient they will become to sensitivity of pain.