I've been having a lot of very rough sex with several different partners right now, and the bruises/marks are starting to build up. All partners are aware that I have sex with other people, but they've definitely noticed the marks from other partners. They seem fine with it, but I'm not sure if I'm being insensitive. Even though everything is noncomittal, I think people secretly like the idea of rough sex being "just between us".
If you're not into rough sex, imagine if your hookup buddy had hickeys from some other person they hooked up with.
If you're not into rough sex, imagine if your hookup buddy had hickeys from some other person they hooked up with.