can someone explain to me why inverted nipples has become some yaoi trope?

Dude, same.

This is like the third yaoi that I read that have inverted nipples. Not that I'm complaining, but just confused...

I gave up wonder that like four stories ago. (⌒▽⌒)

This is my first time reading yaoi where the uke has inverted nipples.....and I'm almost out of yaoi to read

Actually I'm kinda confused with "inverted nipples" what or how or ???? CAN SOMEONE EXPLAIN

It's basically where the nipples kinda just go inward due to how the skin or whatever folds. i have it and I never thought of it being a big deal but it's a yaoi thing now I guess

Wow, i get it now.... hmm I don't even know what to think about my nipples now. Does that make me sexy, weird, who knoes (●￣(ｴ)￣●)