Sensei, Zenbu Dasasete Kudasai

Akira realizes that Koki, the guy he'd been crushing on, is going to become his stepdad. He feels guilty about wanting to touch himself while thinking of Koki... so guilty in fact, that he can't seem to like it anymore!! Right when he's trying to no avail, his high school teacher, the poker-faced Mr. Tojima finds him in a dark alley... and helps him finally release. Akira can't seem to forget the look on Mr. Tojima's face as he helped Akira and decides he'd rather live with Mr. Tojima than with his mom and Koki...

(Source: Renta!)