It was a bl where one guy had inverted nipples and the other had a tongue peirceing (⊙…⊙ ) also I think one of them had pink hair on the cover#－.－)
Assorted Wildness?
I think? https://www.mangago.me/read-manga/ore_no_kanbotsu_chikubi_ga_senpai_no_shitapi_de_tachimashita/
https://www.mangago.me/tag/inverted%20nipples/
It was a bl where one guy had inverted nipples and the other had a tongue peirceing (⊙…⊙ ) also I think one of them had pink hair on the cover#－.－)