Under the penis there is a small bag of skin containing the testicles. There are two of them and they produce sperm and testosterone. Testosterone is the male sex hormone and it makes pubic hair grow and boys’ voices become deeper. Semen is the fluid that carries the sperm. Sperm makes babies when it joins up with women’s eggs. Most of the time sperm is inside the body. There is only one exit for the sperm, which is through the hole at the end of the penis, called the urethra. When the penis is soft, that hole is used to urinate; when it is erect, it is used to release semen.
An erection occurs when the penis fills with blood and becomes hard and straight because a boy or man is sexually excited. Erections can happen when boys fantasize and think about sexual things, or sometimes for no reason at all. Boys do not have any control over when this will happen. It is very common for boys to wake up with an erection in the morning. While asleep at night, a boy’s penis will probably become erect and then go down about five to seven times. This is completely normal and healthy. Having erections is not a sign that a boy needs to have sex.
When the penis is erect, a boy will find that he cannot urinate easily because a muscle closes off the bladder. He will have to wait until the erection goes down before he can urinate. Ejaculation is when semen comes out of an erect penis due to sexual excitement. A man does not have to ejaculate every time he has an erection. If he waits, the erection will go down without causing any harm.
When a boy begins puberty, the ejaculated semen tends to be slightly clear or yellow. As the boy grows into an adult, he begins making a large amount of mature sperm, and his ejaculation will probably become more whitish. Boys are not born with sperm; they begin to produce them during puberty. A boy begins to produce sperm and continues to produce them through his entire life. If the sperm is ejaculated into the woman’s vagina, she may become pregnant. The semen can also carry diseases that could infect another person.
A wet dream is when a boy’s penis becomes erect, and he ejaculates while sleeping. This causes the boy’s underwear or the bed to be a little wet when he wakes up. If a boy does not know about wet dreams, he could be worried or confused. Wet dreams are completely natural and normal. A boy cannot stop himself from having wet dreams.