APA Dictionary of Psychology

orgasm produced from stimulation of the vulva (including the clitoris and labia). Sex researchers Josephine Singer and Irving Singer proposed in 1974 that there are two types of orgasm, vulval orgasm and uterine orgasm, the latter involving deep vaginal penetration that results in contractions of the uterus during orgasm. Uterine contractions are said not to occur with vulval orgasms; they are also said to result in a more complete or satisfying orgasm from intercourse than from stimulation of the vulva alone. However, many women have reported that whether uterine contractions accompany orgasm does not depend on the type of stimulation or sexual activity but rather on how intense the orgasm is, and that the most intense orgasms occur during activities such as cunnilingus or vibrator stimulation of the clitoris. See also vaginal orgasm.