COPULATION: UNDERSTANDING THE MECHANICS IN A MAN

Our knowledge of the detail of what really happens during sexual arousal was, until about twenty years ago, very patchy indeed. The pioneering work of Dr William Masters and Dr Virginia Johnson in the USA changed all that and now many other researchers have repeated and extended their work.

In a man-A man usually starts to become sexually aroused in his head. He is ‘turned on’ by something erotic (either in reality or fantasy) and this mental change sends nervous impulses down his spinal cord to his genitals. In response the spongy tissue of his penis becomes filled with blood, causing the organ to stiffen and change from the limp, downward-hanging organ it usually is to a protruding, rod-like one. This is called an erection. During these changes the man’s heartbeat quickens, his pupils enlarge, his blood pressure rises, his breathing quickens, his nostrils flare, his muscles tense, he sweats a little and he feels sexually excited. This is called the excitement phase of his sexual response. His scrotum becomes tenser and thicker and the testes themselves are drawn up tightly against the body.

It is possible for all these changes to occur and the man then to go back to his normal

pre-excitement phase. Apart perhaps from feeling somewhat let-down, he will return to normal within minutes. Most often though, having got this far, he will go further either by masturbating or by copulating.

The penis now swells even more and its tip (the glans) becomes purplish blue and the contents of the scrotum increase in size. This is the plateau phase and it is more difficult to return to normal from this than from the earlier excitement phase.

The next stage is the orgasm itself. The intensity of sexual arousal is now so high that the man has to ejaculate. Surges of nervous impulses now run back and forth from his nervous system to his genitals and the passages that run from the testes to the penis’ contract (along with local muscles) to squirt semen out of the end of his penis. Once an orgasm is near there is nothing a man can do to stop it — it takes him over. At ejaculation a small quantity of semen shoots out of the penis, often for some distance, and is associated with a wonderful sensation deep in the pelvis as the prostate gland (previously swollen with fluid) discharges its contents. A series of four or five contractions follows at a rate of about one every 0.8 of a second, each producing a smaller volume of semen than before until the tubes carrying the semen are empty. Eventually the contractions cease and the man relaxes. His erect penis returns to its normal size and he feels relaxed and even sleepy. The colour and consistency of semen varies a lot with how long he has been continent. There is no way of judging the quality of semen by its appearance or its volume. Each ejaculation (about a teaspoonful) contains millions of sperms, any one of which could make a woman pregnant.

Once the man has ejaculated, he may take several hours to become arousable again. Younger men have a shorter refractory period and are arousable again sooner than older men. Some boys can have repeated orgasms just like most women. There is absolutely no harm or danger in ejaculating several times a day but it can be tiring. There is no truth at all in the notion that men have only a certain fixed amount of semen which can be ejaculated — every healthy man can ejaculate semen many times a day for the whole of his life and still suffer no adverse

side-effects.

The whole male cycle can be achieved very quickly, especially in teenagers and young men who become aroused and ejaculate in a few minutes. Things are rather different in women.

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