1. Excitement

The Uterus
The uterus also begins to swell and is pulled upward into the abdomen, thus contributing to the lengthening of the vagina mentioned above. During sexual excitement, the nipples of the breasts become erect and maintain this erection throughout the other phases. However, since the dark area around each nipple, and, indeed the whole breast, soon also becomes engorged and swollen, the nipple erection itself gradually appears less conspicuous.

Muscle contractions and sex flush
Mounting sexual tension further produces voluntary and involuntary muscular contractions in various parts of the body as well as a rise in pulse rate and blood pressure. In addition to all the above signs of growing sexual excitement, most women also show a so called sex flush, i.e., a red rash which begins in the stomach area and then spreads to the breasts and neck. This rash lasts through the orgasmic phase.