Let’s talk for a minute about how sexual arousal works.
I’m going to describe sexual physiology in two different ways. First I’ll describe it according to the most widely used model of human sexual response. Then I’ll describe it in terms of a much newer theory, which leaves a lot of questions unanswered, but which can be very useful in understanding the whys and wherefores of sexual response.
In general, sexual arousal is the process of generating sufficient sexual tension so that your body crosses its threshold and releases all that tension in the explosive sensations of orgasm. The traditional model for thinking about this process is Masters and Johnson’s four-phase model.
Excitement. The first phase is all about the rapid accumulation of tension. As you are stimulated, the blood vessels in your vagina and clitoris relax and fill with blood. Your heart rate, respiration rate, and blood pressure rise, and the erectile tissue all over your body (nipples, earlobes, lips, wings of the nostrils) swells and darkens.