A woman's orgasm begins in her clitoris, which is the counterpart of the man's penis. It is preceded by an erection of the clitoris and a moistening of the opening of the vagina. When a woman goes through a full orgasm, her uterus, vagina, anus and pelvic muscles undergo a series of rhythmic contractions. Most women find these contractions very pleasurable. Rubbing or applying other consistent pressure against the clitoris is usually needed to help the woman have an orgasm.