If a recent history of the subject is to be believed, the average man or woman will spend 20 seconds a week in orgasm—or, to extrapolate, around twelve minutes a year or ten hours in a typical lifetime. For something that takes so little of our time, the orgasm occupies a grossly outsized portion of our economy, science, and cultural imagination. There’s no shortage of handbooks—ancient and modern—that can advise you about the best ways to satisfy your lover. If we want to say something is good we describe it as “better than sex”; anything that tastes delicious or illicit is “orgasmic”; and Arnold Schwarzenegger is even able to describe flexing his biceps as “as satisfying as ejaculating.”

For ancient medics the orgasm was what Thomas Laqueur, author of Making Sex, has called a “bodily signal of a cycle of mortality and generation.” Ancient thought held that certain conditions—sluggishness, for example—were caused by an excess of phlegm in the body. The congestion could be relieved by ejaculating; Aristotle actually calls semen “the secretion of an excrement.”

Simultaneously, semen was believed to be the purest form of blood, which contained, naturally, the very essence of life. In this way the male orgasm was not just a prerequisite for procreation, but could also regulate the temperature and the disposition of the body; it kept a person in balance. I say person because many ancient medics believed in a “two seed” model of procreation in which both men and women ejaculated and contributed “seed” to the generative mix. The second-century CE doctor Galen even thought he had discovered female seed when he observed fluid in the horns of the uterus (the fallopian tubes, to you and me).