ass_visible_through_thighs...
-honestly, some of the tags just...who invented this? Can't it just be spread_legs_kneeling?

Some of the posts under that tag feature clearly standing characters with, frankly, their ass_visible_through_thighs. Better than my first impression, where I assumed the tag was referring to see-through phantom thighs through which we could see ass.

It was gluteal_fold, but I suppose that's something most wouldn't immediately think of.

Irrelevant, but in honestly, I find this version funny, lol.