Fudanshism - Fudanshi Shugi

Miyano Amata, known as the "Perfect Prince" for his intelligence, looks, and cool personality, is asked to substitute for his sister as an attendant at a doujinshi convention disguised as a loligothic girl. There he meets a girl from his class and they become friends, but he must crossdress in order to be with the girl while learning about the fujoshi fandom.

Notes:

? Fudanshi = BL fanboys: Some may be gay, some may be straight. More info can be found here.

? Fujoshi = (Literally) Rotten girl: A pejorative Japanese term for female fans of manga and novels that feature romantic relationships between men, often with the implication of yaoi concept.