If the corruption of Holly continues/escalates, there should be ample "reason" on her part to try out something
black different
As for Marcel himself...the underage thing...we know next to nothing about him, maybe that's his thing?
Or maybe Ivy has a way with him too..."Say Marcel, my friend over there needs some attention, your kind of attention...?"
I dunno, but it isn't really that far-fetched
if Holly goes further down the rabbit hole.
(she can do better than cardboard Mark or whatever he's called)