The sexual response cycle in males is similar to that of females, with vasocongestion and myotonia leading to physiological changes in the body (see Figure 10.5). However, in men the four phases are less well defined. During the excitement phase, the penis, like the clitoris in women, begins to fill with blood and become erect. Erection begins very quickly during excitement, generally within 3 to 5 seconds (although the speed of this response lengthens with age).

Excitement Phase The excitement phase of the sexual response cycle in men is of­ten very short, unless a man uses deliberate attempts to lengthen it. Often this causes a gradual loss of tumescence (too-MESS-cents; the swelling of the penis due to vasocon­gestion), which is referred to as detumescence (dee-too-MESS-cents). Distractions dur­ing the excitement phase (such as a roommate walking into the room) may also cause detumescence. However, once the plateau stage is reached, an erection is often more sta­ble and less sensitive to outside influences. It takes men less time to reach the plateau phase than women because women have more intense pelvic congestion.

During the excitement phase, the testicles also increase in size, becoming up to 50% larger. This is both a vasocongestive and myotonic response. The dartos and cremastic muscles pull the testicles closer to the body to avoid injury during thrusting (see Chapter 5 for more information about these muscles). If sexual stimulation were to stop at this point, the swelling in the testicles could be uncomfortable.

Plateau Phase All of these physical changes continue during the plateau phase. Some men may experience a sex flush, which is identical to the sex flush women expe­rience. In addition, it is not uncommon for men to have nipple erections. Just prior to orgasm, the glans penis becomes engorged (this is comparable to the engorgement of the clitoris in women). At this point, a few drops of preejaculatory fluid may appear on the head of the penis.

Orgasm Phase Orgasm and ejaculation do not always occur together (see Figure 10.5). In fact, there are men who are able to have orgasms without ejaculating and can

Question: Does the condition "blue balls" really exist?

The Sexual Response Cycle in MenThe concept of blue balls refers to a pain in the testicles that is expe­rienced by men if sexual arousal is maintained for a significant period but is not followed by an orgasm. It is true that the pressure felt in the genitals, which is caused by vasocongestion, can be uncomfort­able at times. However, this discomfort can easily be relieved through masturbation. Women also experience a similar condition if they are sexually aroused and do not reach orgasm. There can be pressure, pain, or a bloating feeling in the pelvic re­gion, which can also be relieved through masturbation.

have several orgasms prior to ejaculating. Although it is rare, some men are capable of anywhere from 2 to 16 orgasms prior to ejaculation, though the ability to have them de­creases with age (Chia & Abrams, 1997; J. Johnson, 2001).

If orgasm and ejaculation occur at the same time, ejaculation can occur in two stages. During the first stage, which lasts only a few seconds, there are contractions in

SEX in Real Life