It's because sex recently (in the last 20 years) switched to an Elo ranking system. So if you have sex with someone with a much higher skill rank, you'll jump up in rank commensurately. And, unfortunately for you, the converse is also true.

It's because sex recently (in the last 20 years) switched to an Elo ranking system. So if you have sex with someone with a much higher skill rank, you'll jump up in rank commensurately. And, unfortunately for you, the converse is also true.
just another way skill-based matchmaking ruins the experience of casual players who just want to have a good time without sweating too hard
Yet another way the Electric Light Orchestra has ruined my sex life