Does anyone know the manga (yaoi) about a student who has inverted nipples and another student tricks him into thinking he can fix their inverted nipples?
This one? http://www.mangago.me/read-manga/ore_no_kanbotsu_chikubi_ga_senpai_no_shitapi_de_tachimashita/
I think you're talking about Seishun Kinema
Does anyone know the manga (yaoi) about a student who has inverted nipples and another student tricks him into thinking he can fix their inverted nipples?