Tsuushou F Ken ni Youkoso!

From Jcafe24:

Narumiya Yutarou is just a typical high-school boy, but he had an one abnormal secret that couldn't tell anybody. He had a syndrome that he couldn't help to follow his eyes towards girls about little thing like when girl is fixing knee socks and so, and almost fantasizes about it. Even to the extents to do that with his childhood friend and to make it worse, sometimes to his mother. One day there was a love letter and he was called after school. Who waits for him was a Kamiyashiro Touko who invite him into F research club.