Ijimete-gokko.

Yuka-chan, a university student, and Mahiro, a working man, have been dating for six months. They are so pure that they are nervous to even hug each other. But one day, Yuka's "secret" that she didn't want him to know about is revealed to Masahiro, and their relationship slowly starts to go strange...!　A cute, slightly weird, new kind of SM romantic comedy!

(Source: Bookwalker)