Context. If I don’t know them and they’re creeping on me it puts me in a weird position as I don’t know them or how they’ll react if I say no.

If I do know them, but feel uncomfortable, that should be obvious as I will nervously laugh a lot and try to change the subject/end the conversation. I find a lot of guys don’t understand/ won’t accept this which is never fun, to put it mildly.

If we know each other and I act creepy back then you know it’s cool.

Basically, if people seem uncomfortable, stop. If they tell you to stop, stop. It’s pretty simple most of the time. But then again human communication can be complicated.