But she gradually develops a crush on her best friend Mei and secretly has the hots for her own mom!
Normally Osamu isn't particularly effeminate. He looks quite feminine when trying to pass as a girl but his original reason for crossdressing has to do with him falling for a straight boy.
The characters think he's about to have an Unsettling Gender Reveal when he starts flirting with a male actor who played a female role in a kabuki play.