In medieval Europe, Christian clerics compiled penitentials, handbooks with prescribed penances for commonly-heard sins, which they could consult when hearing confession. These books varied in content region to region, but were almost universally used from ~590 (when Columbanus was establishing monasteries in Europe and brought his penitentials with him) until around the 13th century. A fair number of the penitentials we have or have details about are dedicated largely to sex, with more than half the sins described inside being sexual. Sexual sins include doggy-style sex, the use of aphrodisiacs, masturbation, contact with menstrual blood, "fondling" (which may mean manual sex), oral sex, anal sex, French kissing, and consumption of semen, these apparently being common-enough sins that priests in many areas would ask these questions of every man who had not given confession in some time. Penitentials around what is now France sometimes ban sex on Saturday, Sunday, Wednesday, and/or Friday, during Lent, the week after Easter, the month of Christmas, during pregnancy, during breastfeeding time, during menstruation, and/or during daylight.

Bishop Theodulf of Orléans (750-821, bishop 798-818) warned priests to stop asking these questions of people, because he believed it gave people new ideas about what to do sexually, and would increase their propensity to sin.

There are many vices recorded in the penitential which is it not proper for a person to know. Therefore the priest ought not to question him about everything, lest, perhaps, when he goes away he be persuaded by the devil to fall into one of the crimes of which he had been previously ignorant.

It was popularly believed that violating these sexual rules would result in the birth of children with birth defects.

This doesn't address fetishes directly, but it gives you an idea of the sexual culture and attitudes of the time and indicates that yes, there was definitely more of a social stigma back then. One thing that does seem to have been much more common is bestiality; but it was definitely not publicly acceptable or even more acceptable than today, just more common.

(Pierre Payer, "Sex and the Penitentials"; Vern Bullough, "Sexual Practices and the Medieval Church"; Uta Ranke-Heinemann, "Eunuchs for Heaven")

I'm not sure if you're allowed to add questions to a question but this also has me curious about the marriage bed and concept of modesty in medieval Europe. If someone had that inclination would it be accepted to explore or was sex more of a puritanical only for the purpose of procreation type thing? Or did it vary much?

Here’s an excerpt from the Canons of Theodore of some of the official punishment for different sexual acts:

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. If he fornicates interfemorally (between the limbs), he must fast for 1 year or the 3 40-day periods. If he defiles himself (masturbates), he is to abstain from meat for four days. He who desires to fornicate (with) himself (i.e., to masturbate) and is not able to do so, he must fast for 40 days or 20 days. If he is a boy and does it often, either he is to fast 20 days or one is to whip him. If a woman fornicates [with another woman?] she must do penance for 3 years. If she touches herself in the same way, i.e., in emulation of fornication, she must repent for 1 year. One penance applies to a widow and a virgin; more (penance) is earned by her who has a husband if she fornicates. Whoever ejaculates seed into the mouth, that is the worst evil. From someone it was judged that they repent this up to the end of their lives.

Were people with fetishes executed for them? Something like purging the devil?

Hi there! I just thought I’d throw in a quick interjection to let people such as the OP who are interested in some of the nitty-gritty details of historical sexuality and who ask these types of question to consider moving their purview into the Early Modern or Modern era.

I appreciate that some people want to know specifically about pre-modern sexuality and we’ve got a couple great users for that, however questions such as this which ask for a high level of “detail” about sexual practices, or for information about sexuality that was divergent to contemporary standards, suffers two major problems:

• A lack of reliable sources. With literacy rates and the cost of notation what they were, it’s difficult to find credible sources that have a “real” depiction of medieval sexuality. One of the best (or at least most famous) medieval sources on sexuality and home life are the legal records from the case of Martin Guerre, but stuff like this this is pretty far removed from what you’re asking about. Aside from legal records, religious works are the only other major source for this sort of thing and, as cautioned by u/haimoofauxerre, they tend towards sensationalism and obviously contain a lot of biases.

• Anachronism. You use the term “fetishes” and “BDSM” in your post, neither definitions of which would make any sense to someone living before the 19th century. Everything about our current sexual culture is wrapped up in concepts that have only developed very recently. Consequently when you try to draw connections between our sex lives and someone who lived 500+ years ago pretty much everything gets lost in the translation. While there may be individual instances that resemble stuff your describing, there was certainly no formal understanding of it, never mind standardized social practices.

In contrast to this the Early Modern and Modern periods have a large volume of sources that concerns both “real” and “literary/pornographic/philosophical” sexuality. Want to hear Samuel Pepys discuss his sexual practices with his wife, masturbatory habits, and infidelity in his diary? No problem! Want to hear about the practice of flagellation as a standardized sexual practice in England? I got you. In addition to the abundance of sources, you can partially conceptualize these histories in relation to modern practices because they’re so much more topical to our own understandings. Obviously there’s still a lot of challenges to overcome but it’s possible to draw out parallels and predecessors, and the subject is way more vibrant than you might assume.

TL DR; If you want to hear some truly dirty stuff I suggest you stop harassing the medievalists and antiquarians and get at the Early Modern/Modern scholars. I am sitting on piles of kinky pornography waiting for you.