Sex is a complicated thing. Most people want it; getting it and doing it well have been elusive goals for thousands of years. (Just ask Cosmopolitan.) But modern-day Americans can be thankful that we are not trying to have sex in Medieval Europe. Because what was allowed and what was not was, if anything, even more complicated back then.
A blog aptly named The History Blog has a post about just how complicated. The blog took a look at a penitential—a handbook of sin, meant for those who listened to confessions. It told the confessor what the appropriate penances were for each transgression: a confessor couldn't be expected to memorize them all, because there were way too many and they were way too complicated. The History Blog points out a small excerpt from the Canons of Theodore:
Whoever fornicates with an effeminate male or with another man or with an animal must fast for 10 years.
Elsewhere it says that whoever fornicates with an animal must fast 15 years and sodomites must fast for 7 years.
If the effeminate male (bædling) fornicates with another effeminate male (bædling), (he is to) do penance for 10 years.
Whoever does this unintentionally (unwærlice) once must fast for 4 years; if it is habitual, as Basil says, for 15 years if he is not in orders and also one year (less?) so as a woman does. If it is a boy, for the first time, 2 years; if he does it again, 4 years.
If he is a boy, for the first time, 2 years; if he does it again, 4 years.
There’s more than that. A lot more. The History Blog explains why there are so many rules about sex:
The penitential writers saw marital sex as a concession, not as a right or even a gift from God. The pleasure it brought was inherently sinful, a gateway to lust, so sex within marriage should be carefully contained and scheduled to ensure the most possible procreation and the least possible pleasure. Married couples had to abstain regularly or the very state of their marriage would degenerate into an illegitimate and sinful union. Even the children born of sex during a period where the couple should have abstained — mainly based on the Church’s liturgical calendar and on the wife’s reproductive cycle — were to be considered bastards.
Modern scholars of medieval religion have a hard time keeping track of which types of sex were okay and which were sinful, too. In scholar James A. Brundage's Law, Sex, and Christian Society in Medieval Europe, which covers the many rules and regulations of the bedroom, there is a really excellent flowchart for those who are trying to stick to Medieval sex rules. The majority of the lines lead to “STOP! SIN!” Only in a handful of cases can would-be sexual partners “GO AHEAD! But be careful: No fondling! No lewd kisses! No oral sex! No strange positions! Only once! Try not to enjoy it! Good luck! And wash afterwards!”