I've been looking high and low for a certain manga.
A girl and a crossdressing boy having Urethral sex with each other. the story went that, when they were kids, they thought that sex was when you put your dick in the peehole, and so they spent years stretching out their holes to the point where they have to wear tampons in their urethra's to keep from constantly pissing their pants. they also suck on the tampons to taste each others pee.

the comic consists mostly of them drinking each others piss and fucking each others urethra's. and I believe the boy was crossdressing too.

It has been a few years since I've seen it floating around so I may be off on some points. I think they may have also been siblings, but they could have also just been childhood friends.


the image is unrelated (its from - Mitsuha-chan Change (Kimi no Na wa)