Plateau Stage
. During the plateau stage, vasocongestion peaks and the processes begun in the excitement stage continue until sufficient tension is built up for orgasm to occur. Breathing rate, pulse rate, and blood pressure increase. The man's penis becomes completely erect and the glans swells. Fluid secreted from the Cowper's gland (located near the urethra, below the prostate) may appear at the tip of the penis. This fluid, which nourishes the sperm, may contain active sperm capable of impregnating a woman. In women, the breasts continue to swell, the lower third of the vagina swells, creating what is called the orgasmic platform, the clitoris retracts into the body, and the uterus enlarges. As the woman approaches orgasm, the labia majora darken.