Plateau
Increasedvasocongestionin the vagina causes it to swell, decreasing the size of the vaginal opening by about 30%. The clitoris becomes increasingly erect, and the glans moves towards the pubic bone, becoming concealed by the hood. The labia Minora increase considerably in thickness, approximately 2–6 times, causing them to spread apart, displaying the vaginal opening. The labia minora sometimes change considerably in color, going from pink to red in lighter skinned women who have not borne a child, or red to dark red in those that have.[citation needed]
Orgasm
Immediately prior to thefemale orgasm, the clitoris becomes exceptionally engorged, causing theglansto appear to retract into the clitoral hood. This is thought to protect the sensitive glans during orgasm. However, there is some doubt that this is the case, since the same engorgement prior to orgasm occurs in the male homologous structure, the penis, the function of which is thought to be to extend the penis as close to the cervix as possible prior to ejaculation.
Rhythmicmuscle contractionsoccur in the outer third of the vagina, as well as the uterus and anus. They occur initially at a rate of about one every 0.8 seconds, becoming less intense and more randomly spaced as the orgasm continues. An orgasm may have as few as one or as many as 15 or more contractions, depending on its intensity. Orgasm may be accompanied byfemale ejaculation, causing liquid from either theSkene's glandorbladderto be expelled through the urethra.