Physiological responses

In men

During orgasm, a human male experiences rapid, rhythmic contractions of the anal sphincter, the prostate, and the muscles of the penis. The sperm are transmitted up the vas deferens from the testicles, into the prostate gland as well as through the seminal vesicles to produce what is known as semen. The prostate produces a secretion that forms one of the components of ejaculate. Contraction of the sphincter and prostate force stored semen to be expelled through the penis's urethral opening. The process takes from three to ten seconds, and is highly pleasurable.

Normally, as a man ages, the amount of semen he ejaculates diminishes, and so does the duration of orgasms. This does not normally affect the intensity of pleasure, but merely shortens the duration.

After ejaculation, a refractory period usually occurs, during which a man cannot achieve another orgasm. This can last anywhere from less than a minute to several hours, depending on age and other individual factors.