Penises vary in size and appearance. The sizes of adult penises vary, but when they are erect (hard), they are mostly a similar size. When the penis is stimulated or a guy is sexually aroused, the penis can grow from being small, limp and soft to larger, erect and hard. This is called an erection. The penis does not contain any bones and is not made of muscle. The penis becomes erect because the tissue inside the penis fills with blood under pressure.
The foreskin is a fold of skin which covers the tip of the penis (glans). It is very important to keep the area beneath it clean. The foreskin should be pushed back daily and the glans gently washed. Sometimes the foreskin is removed surgically at birth in a procedure known as circumcision.
About 1/3 of boys will experience some sort of minor breast development during puberty. This is normal and is usually nothing to worry about. You may notice swelling or lumps under your nipples. Your nipples may also feel tender when clothing rubs against them. The swelling usually lasts around 4 to 6 months, but it may continue for longer. See a doctor if this is worrying you.
Hair will start to grow under your arms and around the pubic area. This hair will be fine and straight at first, and will become thicker and curlier as you get older. You may also find more hair growing on your legs and arms. Hair will also appear on your chin and upper lip.
When should I shave?
Hair that appears on your face will be fine and downy at first and become more bristly as you grow older. You probably won’t need to shave much at first –this will become more regular in your later teenage years. When you begin to shave is your choice. You might like to talk your decision over with a parent or a trusted adult before you begin. You may also like some shaving lessons from someone who has done it before! Some men choose to shave around their pubic area and chest. There is no health reason for doing this. It is a matter of choice. Remember to avoid sharing razors with other people as it can pass on viruses like hepatitis B and C.
During puberty, you can become sexually excited or aroused quite easily and you can ejaculate (or cum) while you are asleep. This is called nocturnal emission, or a “wet dream”. Wet dreams are totally normal. They are your body’s way of getting rid of a build-up of semen in your body. When you wake after a wet dream, your sheets or pyjamas may feel slightly sticky. Sometimes you remember the good feeling in the night, or you may remember nothing at all, it happens to all men and there is nothing to be ashamed of – just put your things in the wash.