yes!!! it's a big bonus for marceline if her partners have piercings (or tats) - she doesn't have any piercings herself even though she's thought about it a few times, jst decided they weren't for her and she'd keep admiring them on others (she's got a couple tattoos though, some in places that you're gonna have to ask real nicely if you want to see) - cupid likes em too, not for any deep reasons they just like a variety of sensation on the occasions they bottom

lilith and seraphina both have a bit of a thing for piercings - it's not gonna make or break any experience with other partners for them, but they enjoy them as a potential medium of pleasure (so mostly Sex Piercings, even tho seraphina ironically doesn't have any she's just got the one in her navel)

[i am hunted for sport before i can say anything about carlisle]