I've only had casual sex a couple of times. Twice so that I was in a bar alone, started to talk to some dude, hung out with them for the evening and ended up going home with them. The first guy texted me from abroad for some years, the second dated me for a few weeks before we realised we're too different, the 3rd I met at a friend's birthday party and ended up having a nearly year-long long-distance relationship with. The fourth, I think, is the only one that actually qualifies as "casual" since I never saw them again even though they tried to text me a couple of times. It was fun, we were part of a random group having an afterparty in a park after the bars had closed and slinked to his place.

It depends a lot on whether or not you have chemistry with the guy and how you both feel about it. It can be good fun, I suppose, both recognising the situation and that you're in the same boat so to speak, and especially if the mutual feeling is good and friendly it can be a lark, but it requires that you meet the right dude for the one night stand. Which is rare. Most of the time, even if there are interested guys, I just haven't gotten the right effortless feeling.

I don't know what it would be like if it was really someone you don't care about but just rate qt enough to fuck. Personally I can't bring myself to do something like that