Boku Girl

Suzushiro Mizuki is a 1st year high school student who has the difficulty of constantly being mistaken for a girl. It's so bad that he's endlessly rebuffing the confessions of many men. Even the girl he has a crush on seems to think of him more as one of the girls rather than as a potential love interest. Meanwhile, the trickster god Loki has grown bored with playing her tricks on her fellow gods. Turning her attention to the mortal world, she targets Mizuki for her next round of fun. The result: Mizuki wakes up with budding breasts and a missing part of his anatomy. What else is in store for Mizuki and how will he deal with it? (Source: MyAnimeList)