Even though sexual relations are considered different now than in the Middle Ages, people across time have always dealt with similar issues, just in different ways. For example, people have oft tried to figure out how to have intercourse without getting pregnant. People have the same concerns about performance or lack of experience. And people have been scared about the prospective sinfulness of their intimate lives for centuries. Literally. Regardless of geographic location or point in time, those actively engaged in intimate relations have also shouldered concerns about sexual health and prosperity.
Although society's perspective on sexuality may have changed since the Middle Ages, some details of how people got down to business are surprisingly still relevant. Albeit, the reasoning may not be quite so similar. How people sexually interact may have changed throughout the centuries, but fundamental principles still ring true: humans are drawn to the exploration of the body and the pleasures it may afford.
According to the Catholic Church, having intercourse in the missionary position really was the only way to go. Other positions posed the risk of confusing gender roles or emphasizing the pleasurable aspects of the act, rather than its role as the engine of procreation.
In fact, those discovered deviating from the standard position faced punishment - depending on the specifics of the transgression.
Since procreation was so important, men who had trouble performing in bed posed a big problem. If a man couldn't become erect, their genitals would be physically investigated by the Church. If an irresolvable problem was discovered during the investigation, a marital separation could be granted.
In some cases, "honest women" were brought forth to examine the man-in-question to determine whether the allegation of dysfunction was true.
In the Middle Ages, engaging in rear entry intercourse was considered both sinful and prohibited. However, as records from 1400-1550 in Southern Netherlands show, both men and women were quasi-regularly put on trial for exactly this act.
This suggests, of course, that while looked down upon, this act of intimacy was also relatively widespread among both genders.
Unlike in most countries today, sex work in the Middle Ages was seen as a necessary profession. For a while, the Church tolerated this type of work in so far as it helped counter negative public image. When the city of Florence began to get a reputation for being the home to many homosexuals, the city began to encourage the establishment of brothels in order to keep men's homosexual tendencies at bay.
In this sense, the Christian society used working women "to promote decency" and "regulate the behavior of men."