I don't care if you guys decide to say "it's working as intended", the rear-only underwear looks so out of place and doesn't fit like any underwear I've ever seen. If you refuse to make it into a thong-style underwear (if you have the costume you know what I mean) at least make it dye-able and in the style of the default "nude underwear" setting. I've seen it on these forums and reddit, nobody likes the style design.
In my opinion, it looks as if someone forgot to animate/style the entire "buttocks" area and sent it into the game without the ability to dye it or allow skins/tattoos to weave through it. The costume is excellent otherwise, but the massive hugging underwear on the rear-end only is quite the dealbreaker.