Healthy lives for young people
My Body

Penises and testicles

The penis has two main functions; urination (carrying urine or wee out of the body) and ejaculation (delivering semen from the testicles.) The testicles are where semen is produced and stored.

The penis and testicles are often surrounded by myths; often about size and shape but everyone’s are different, and, like other parts of you, penises and testicles come in all different shapes and sizes.

Anatomy of the penis and testicles

The penis is made up of the shaft and the glans (or head) of the penis. Between the shaft and the head is the corona – a sort of ridge that separates the two.

At birth, the penis is covered by the foreskin (a hood of loose skin that surrounds the penis). The underside of the penis has a frenulum (or frenum) which connects the foreskin to the base of the head of the penis.

Running up the inside of the penis is the urethra. The urethra is the tube that carries urine from the bladder, outside of the body. During ejaculation, the urethra is also used to carry semen out of the body. Sperm is produced in the testicles and is carried from the testicles via the prostate gland (where prostate fluid is added to the sperm for nourishment, this is then called semen) before travelling out of the body through the urethra.

The two testicles (sometimes called testes and commonly referred to as ‘balls’ or ‘nuts’) hang outside the body, just behind the penis in a small pouch of skin called the scrotum. The testicles are roughly the size of small plums, they are often about the same size although it is common for one to be bigger than the other, or for them to hang at different heights.

Illustration of the inside of a male penis

The foreskin and circumcision

When the penis is soft, the foreskin is the fold of skin that covers the head of the penis. When the penis is hard, the foreskin moves back, so the head of the penis is exposed. Some men have a foreskin long enough to cover the head of their penis even during an erection.

Men are born with a foreskin but some are circumcised, usually as babies. This is the surgical removal of some or all of the foreskin and is usually carried out for a variety of reasons. A circumcised penis will no longer have a foreskin covering the head. Some men who are not cisgender undergo circumcision for other reasons.

Tight foreskin?

Some men find that they have a tight foreskin, which does not easily roll back over the head of the penis when they have an erection. This can feel really uncomfortable.

The foreskin being too tight is known as phimosis and unless it causes symptoms this isn’t usually a problem. If it does cause symptoms these can include;

  • redness
  • swelling
  • discharge
  • balanitis (inflammation of the head of the penis or ‘glans’)
  • balanoposthitis (where both the glans and the foreskin are inflamed).

A tight foreskin can also be associated with sexually transmitted infections or other skin conditions such as eczema or psoriasis.

If you have any swelling, discharge, or redness, or are worried you should seek advice from a doctor or nurse. Balanitis and balanoposthitis can be treated with a combination of good hygiene and antibiotics/antifungal cream depending on the cause of the infection. Steroid creams can be prescribed to help with a tight foreskin, and in some cases surgery may be considered to remove the foreskin.

Seek help

If you are unable to pull your foreskin back, you should seek medical advice. If you can pull your foreskin back and it gets stuck and won’t retract (paraphimosis) you should go to A&E.


Many young men worry about the size of their penis, and feel self-conscious that it’s perhaps too small. However this often due to the fact that people exaggerate or over-estimate the average size of a penis.

In general, the average adult penis size is usually about 5-10cm or 2.5 to 4 inches when soft, and about 13-18cm (5 to 7 inches) when erect.¹ The average girth (all the way around) when erect is approximately 12-13cm (4.7-5.1 inches). When flaccid (soft) the length of a penis can also vary depending on other factor such as temperature.

The size of your penis does not have an effect on how good you are at sex. Every penis is different, and you just need to learn how to use it! And bear in mind that your penis will always look smaller to you because you are looking down on it.

Also, when erect, penises can curve up, down, or curve to the left or right. There is nothing unusual about having a curved penis.

During puberty, usually between the ages of 11-18 the penis and testicles will grow, however they don’t stop growing completely until around 21 years old.

Pubic hair

Pubic hair grows around the top of your penis and testicles and can sometimes grow around the top of your thighs or stomach. It can be coarse or fine, straight or curly, dark or light – it’s all completely normal.

Some people like to remove some or all of their pubic hair. Lots of people also choose to leave their pubic hair exactly the way it is. Everyone’s different and the way you choose to keep your public hair is entirely up to you.


When you become sexually aroused the sponge-like tissue of the penis fills with blood and becomes hard, this is known as an erection. However you can’t always choose or control when you get an erection, and they can happen at the most awkward and embarrassing moments. This is especially true in your teens, when your hormones are raging and it’s normal for erections to appear without any warning, even when you’re not thinking about anything sexy whatsoever!

If you get an erection at a very awkward or inappropriate moment, you could put a jumper on your lap to cover it. If someone notices, try not to react. The less you react, the sooner they’ll get tired of making a scene about it.

You may find it helpful to think of something really dull and boring and unsexy, and if you concentrate hard enough, this should make your erection disappear.

Getting very frequent erections tends to settle down as you come out of your teens. The chances are your mates have the same experiences, but maybe don’t chat to you about it, as they may find it embarrassing to talk about.


Masturbation (also known as solo-sex, wanking, playing with yourself, etc.) is stimulating yourself for sexual pleasure. It can be a good way to get to know your body and what makes you feel good sexually.

Besides being safe and fun, it helps you know how to please yourself so that you can let others know how they can please you. There are lots of myths about masturbation but it’s fine to masturbate as often or as little as you like. Some people don’t masturbate at all and that’s ok too.


You should gently wash the penis and testicles with warm water once every day, and if you have a foreskin, pull it back gently and wash underneath. If you don’t keep your penis clean a yellowish-white creamy substance called smegma will start to build up on the head of your penis, and under your foreskin.

Smegma is a natural lubricant that keeps your penis moist, but if it starts to build up it can have an unpleasant smell (a bit like cheese) and become a breeding ground for bacteria. This can then cause balanitis (redness and swelling of the head of the penis).

Men with foreskins need to be extra careful about washing smegma away. Try washing carefully under your foreskin, and see if the yellowish stuff disappears. You might like to use some un-perfumed soap or shower gel (to avoid irritation), and gently rub it with your fingers. Once it goes, make sure you wash under your foreskin every day, to avoid smegma building up again.

There are other types of infection that affect the genital and anal area including thrush, cystitis, urethritis and proctitis.

Lumps and bumps on the penis

The penis can have lumps and bumps and in most cases these are harmless. Lumps and sores can be caused by hygiene, sex, sexually transmitted infections or skin conditions such as molluscum contagiosum (a viral skin infection), and in very rare cases penile cancer.

You can read more about the causes of lumps and bumps on the penis on the NHS Choices website. If you are worried or notice something that isn’t quite right you should speak to a doctor or nurse.

Checking your balls

It’s common to get spots and bumps on the scrotum, and they are often completely harmless. However, it’s important to get to know your testicles, so that you can tell if something doesn’t feel quite right.

It’s a good idea to examine your testicles when you’re in the bath or shower. Support your scrotum in the palm of your hand, and become familiar with the size and weight of each testicle. Examine each testicle by rolling it between your fingers and thumb. Your testicles should feel smooth, so gently feel for lumps, swellings, or changes in firmness. Check for lumps on the surface or within the body of each testicle.

If you notice a lump, or something doesn’t feel quite right, or you get sharp pains or a dull ache in your testicles, it’s important to see a doctor or nurse. Other reasons to go to the doctor are if you get a sensation of heaviness in your scrotum, or a dull ache in your lower abdomen or groin.

There are a number of things that can cause lumps, swelling or pain in the testicles such as some STIs, fluid or cysts but the main reason you are encouraged to check your testicles is because of testicular cancer. While testicular cancer is rare (around 2,200 men are diagnosed each year in the UK) it is commonest in younger men, which is why checking your balls is a great habit to get into.

You can read more about the symptoms of testicular cancer and what to look for and about testicular cancer incidence by age.

When to see a doctor

If you notice any changes, or anything unusual about your penis or testicles, you should see your GP. This could include unusual discharge, tenderness or any lumps and bumps you are worried about. They can be signs of infection, which are important to get treated.

If you have a curve in your penis and this is causing you pain you should see your GP.

If you are unable to pull your foreskin back, you should seek medical advice. If you can pull your foreskin back and it gets stuck and won’t retract you should go to A&E.

Protecting yourself from STIs

Condoms are a method of contraception that protect against sexually transmitted infections (STIs) and pregnancy.

They are made of very thin latex (rubber) and are designed to cover the penis in order to stop the sperm in semen coming into contact with the vagina. Condoms also stop sexual fluids being transferred between partners which provides protection against STIs.

When condoms are used correctly they are 98% effective at protecting against pregnancy and you can get them free from Brook services, contraception clinics, young people’s services, GUM clinics and some GP surgeries.


    Other Stuff you might find useful…

    Real Story
    Body Dysmorphia Disorder: Abby’s Story
    My Body
    Real Story
    Endometriosis: Libby’s Story
    My Body
    My Body
    Real Story
    Thrush: Isabel’s story
    My Body
    Real Story
    Thrush: Marlena’s Story
    My Body
    Real Story
    My first period: Mila’s story
    My Body
    Period FAQs
    My Body
    Keeping clean
    My Body
    My Body
    My Body


    Find a Service near you