Can someone attempt to define what this is? Basically, to my understanding, everyone who lives in a modern civilization has to "repress" themselves to some extent simply to go about day-to-day life. If we didn't, then we would live like cavemen and presumably do nothing but procreate. (This, to my knowledge, is a Freudian concept and one which has been brought up by other thinkers).
To be in a monogamous relationship, a person has to "repress" whatever desire they might have to seek out other partners. The desire itself may be "natural", but infidelity would be considered wrong.
And obviously, behaviors that might exist in nature and serve an evolutionary purpose in the animal kingdom, such as rape, would not be moral or socially acceptable. (For example, sexual aggression exists in chimpanzees, but it would be wrong for humans to engage in this behavior. Though I'm aware that some couples have consensual "rough sex").
https://www.theguardian.com/science/2008/jun/16/neuroscience.psychology
So while I often hear people talk about "sexual repression", I don't know how you would actually define what this is, given that a completely open license to any and all sexual behavior would not be socially acceptable. I've heard some people say that America is a mix of puritanical views on sex and oversexualized consumer culture.