Sensei, Kiite yo

Uta thought that her homeroom teacher was a geek, but she saw him when he was dressed differently. Sensei was actually a handsome rock-n-roll singer!? Since Uta had always wanted to have a boyfriend, she threatened him to "go out with her" and she wouldn't tell anyone his secret! but she ends up really falling in love with her teacher...?!

(Source: Chibi Manga)

Included one-shot: Natsu wa Ginga no Ame ga Furu