The Anatomy of Male Arousal

Our bodies go through a number of changes during sex. Understanding these changes helps us understand both our sexuality and that of our spouse.

Most scientific folk divide these sexual responses up into four phases – arousal, plateau, orgasm, and resolution. This article looks at men. You can read about women here.

arousal

This phase starts with some kind of sexual stimulation – a touch, a sight, or a thought. Blood begins to move to various parts of the body. The lips, nipples (sometimes nipples become erect), earlobes and genitals become fuller and more sensitive. The penis begins to fill with blood and become erect, and the scrotum starts to thicken, pulling the testicles closer to the man’s body.

plateau

With continued stimulation, the penis becomes slightly firmer, may darken in color, and fluid containing sperm may seep out. Over long periods of foreplay, the penis may become flaccid and then harden again. This is perfectly normal. Even if the penis stays erect, firmness will wax and wane to some degree. The scrotum continues to thicken and the testes start to enlarge. The right testicle will rise and slightly rotate first, and then the left will do the same. Heart rate and blood pressure will increase, and a skin flush may appear on the chest, neck or face. Breathing and heart rate increase, and moans or other sounds may be made. As climax approaches the skin of the glans darkens and becomes taught, and the urethral opening may slightly open. Immediately before ejaculation, at the “point of no return”, the sphincter from the bladder closes so that semen can’t move into the bladder, and the prostate and seminal vesicles contract to move seminal fluid to the urethra bulb near the base of the penis.

orgasm

The PC muscles contract to expel the seminal fluid. Much of the seminal duct system contracts, as does the rectal sphincter. There may be foot spasms or contracting facial muscles. Muscles tense, and breathing, heart rate and blood pressure rise further. Because the penis becomes hypersensitive at or immediately after orgasm, a reduction of stimulation during orgasm is desired by most men. This varies from the man who wants all stimulation to end as soon as orgasm starts, to men who want heavy stimulation through orgasm. Men’s orgasms are much shorter than women’s.

resolution

This is when the body returns to normal after orgasm. A fine perspiration may cover the body. The penis becomes flaccid in two stages: partial erection is lost immediately; the remainder is lost gradually, possibly over several minutes. Hypersensitivity of the penis decreases gradually, though some men may find any touch or ongoing thrusting very uncomfortable for some time. After a strong orgasm the penis may spontaneously jerk for a minute or two. The scrotum thins and the testes descend and return to normal size. Breathing, heart rate and blood pressure return to normal, and muscles relax. Continued stimulation may prevent full loss of erection, or resumed stimulation may result in a new erection, but there is period of time known as the refractory period during which it is impossible to have another ejaculation, even if another erection is achieved. The refractory period ranges from minutes to hours or even a day or more. As a man ages his refractory period increases, but two men the same age can have vastly different refractory periods.

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