He slapped my ass once while you were there and he was making a joke. Just because I like bdsm it does not mean I enjoy random people doing things to me, I am not that masochistic in the first place, and I do not enjoy people giving me purple nurples
and slapping me on the back in general. I tolerate them because it's funny for the jokes. I'm neutral about it. It hurts I guess but not enough for me to care in a way that it hurts too much to tell him to stop to ruin the joke, but that's it.
Also, the joke stems from something you don't even know about. So before you go around telling people that keep all that in mind, seriously.
Caught you looking.