射精   Ejaculation
In males, orgasm begins with involuntary rhythmic contractions of the genital ducts and accessory organs (vasa deferentia, seminal vesicles, prostate gland), the urethra, the muscles at the base of the penis and finally the penis itself. The first three or four forceful contractions recur within less than a second, then, as they become weaker, at longer intervals. In sexually mature males, orgasm is usually accompanied by the ejaculation (lat.: throwing out) of semen: As a result of the orgasmic muscular contractions, the accumulated semen is forced through the urethra to the outside where it emerges in several quick spurts. At times, it may be projected a considerable distance; at other times, it may flow out rather gently. The force of a particular ejaculation is not related to a man's strength or virility.