Orgasm itself begins with strong muscle contractions that are felt primarily in the outer third of the vagina that is closest to the outside of the body. The contractions last from four to 15 seconds, and occur at intervals of about .8 seconds. During orgasm, muscles may keep contracting, and blood pressure, heart rate and respiratory rate climb higher. Women frequently report sensations of tingling in the spine, brain and genital areas (Freeing the Female Orgasm, 2).
When discussing the female orgasm, Masters and Johnson continually stress that it is a psychophysiological experience, where the body reflects physically the subjective sensations radiating throughout the individual. Masters and Johnson broke the psychological experience of female orgasm down into three stages. The first is characterized by a feeling of suspension for a brief moment followed by an "intense sensual awareness" (p. 135) in the clitoris that rapidly spreads throughout the pelvic region. The second psychological stage of orgasm, as labeled by Masters and Johnson, is distinguished by a feeling of warmth originating from the pelvic region and spreading throughout the body. The third stage accompanies the involuntary physical contractions described above and is commonly felt in two parts. First there is a strong contraction felt in the vagina, which is then followed by a throbbing sensation that spreads to the pelvis and then onto the rest of the body. An experiment was done in 1982 where they tested pelvic contractions during female orgasm. Eleven women manually stimulated themselves to orgasm on three separate occasions. The pelvic contractions were measured by the use of an anal probe and a vaginal probe simultaneously. Anal pressure had a higher resting baseline and greater amplitude contractions than vaginal pressure. The results showed that the perceived start of orgasm did not correspond precisely with the onset of regular contractions.
