The uke is sneaky and makes the seme believe someone wrote dirty words on his body, and the seme (younger, glasses) sees the words when the uke gets wet from the rain.
Probably this http://www.mangago.me/read-manga/junai_drop_out/
The uke is sneaky and makes the seme believe someone wrote dirty words on his body, and the seme (younger, glasses) sees the words when the uke gets wet from the rain.