Male ejaculation

Male ejaculation, often called simply ejaculation, is the process of ejecting semen from the penis. This usually occurs due to sexual stimulation, but may also occur spontaneously during sleep, and then is called a nocturnal emission, or may occur due to massaging of the prostate or, rarely, due to prostatic disease.

Ejaculation as a process usually is caused by a combination of contractions of the prostate, a muscular gland, and contractions of the urethra, the passage through the penis through which both urine and semen pass out of the male body.

The force and amount of ejaculate vary widely from male to male. A normal ejaculate may contain anywhere from 5 to 15 milliliters (from a teaspoon to a tablespoon). However, some men may barely generate a few small drops, while some men may ejaculate much more than this. The amount of ejaculate is highly dependent on how recent the last previous ejaculation was within a range of the first two days. In other words, an ejaculation soon after a previous ejaculation will be very small, but will be much larger if ejaculation has not occurred for two days or longer.

Some men may be able to shoot their ejaculate several feet or even longer, while the semen may simply ooze out of some men's penises.

The number of sperm in an ejaculation also varies widely, depending on many factors, including the recentness of last ejaculation, the average warmth of the testicles, the degree and length of time of sexual excitement prior to ejaculation, the age, testosterone level, and general fertility of the subject, and the total volume of seminal fluid.

Most men experience a lag time of some half-hour or so between the ability to ejaculate consecutively. This is called a refactory period, during which it is difficult or impossible to attain an erection.

Compare female ejaculation.