Nocturnal emission
A nocturnal emission or wet dream means a person has a sexual orgasm while sleeping. It often leads to ejaculation. Wet dreams can begin after a person goes through puberty. Some young people have their first orgasm this way. According to one book, about 13% of boys had their first ejaculation through a wet dream. They might not understand what has happened to them, if they have not been taught anything about sex.