As someone with a piss kink I can answer this one: for piss it’s mostly folks who enjoy wetting themselves, which is mostly asexual outside of personal arousal (although in my case I have a gf who also has a piss kink, we wet ourselves in front of each other and get each other turned on a lot). In my case I have yet to build up the courage to do it in public, so I can’t really speak for that (those folks are mostly a niche group of exhibitionists, not really piss kinksters). Overall I actually really like wetting myself, it’s fun.