What's the big deal with seeing a girl's underwear, anyway?
As a degenerate pervert myself, It kinda feels like you're getting a sneak peak at what's under or just the thought of being able to take them off is kinds exciting.
This isn't really the worst tbh. I mean, I've read a doujin where a girl put insects, a tube, and more inside her vag to the point that she had to get surgery more than a few times.