During the second phase, called the expulsion phase, the urinary bladder closes to block the possibility of urine mixing with the semen. At this point, muscles at the base of the penis begin a steady rhythmic contraction that finally expels the semen from the urethral opening at the head of the penis.

The Third Phase of Sexual Response
The peak of sexual excitement is reached during the third phase. Involuntary muscle contractions, heightened blood pressure and heart rate, rapid intake of oxygen, sphincter muscle contraction, spasms of the carpopedel muscles in the feet, and sudden forceful release of sexual tension characterize the orgasmic phase.

For men, orgasm generally climaxes in the ejaculation of semen, which contains millions of sperm. Ejaculation consists of two steps. During the first phase, called the emission phase, seminal fluid builds up in the urethral bulb of the prostate gland. As the fluid accumulates, the male senses he is about to ejaculate. This is often experienced as inevitable and uncontrollable.

For women, orgasm also consists of rhythmic muscle contractions, in this case of the uterus, at about the same pace as in men. Tightening of the woman's muscles puts pressure on the man's penis and assists in male orgasm.

For both sexes, barring the presence of some form of sexual dysfunction, orgasm is an intensely pleasurable experience. Indeed, some see it as the most pleasurable experience possible.

The Final Phase of Sexual Response
In this phase, the resolution, the body returns to normal levels of heart rate, blood pressure, breathing, and muscle contraction. Swelled and erect body parts return to normal and skin flushing disappears.

The resolution phase is marked by a general sense of well being and enhanced intimacy and possibly by fatigue as well. Many women are capable of a rapid return to the orgasmic phase with minimal stimulation and may experience continued orgasms for up to an hour.

Males, especially as they age, experience a refractory period of varying duration after orgasm. During this period, men cannot achieve orgasm, although partial or full erection may sometimes be maintained.

The duration of the refractory period can vary from just a few minutes to several days and there is great variability in the length of the refractory period both within and between men.

Copyright 2002 Sinclair Intimacy Institute