Ejaculation is the ejection of semen from a man's penis. This can be accomplished via vaginal intercourse, anal sex, masturbation, oral sex, or even while sleeping (commonly known as a wet dream). Ejaculation usually occurs along with orgasm, although it is possible for the two to occur separately. On average, men tend to ejactulate about one teaspoon of semen each time.
Ejaculating onto a sexual partner can be a real turn-on for some men. Ejaculation of semen into a female's vagina is also the basis for reproduction.