Kyou, Orenchi Yotteku?

Kikuchi is a laid-back, thickheaded, yet softhearted high school boy. He regularly hangs out with his close friend, Seto, at either of their houses after school. One day, after Kikuchi got aroused by porn, Seto suggests helping the other get off. Kikuchi gets hooked on Seto's—who's gay and is apparently used to these things—blowjob and offers to return the favor to show his gratitude (?). When Kikuchi thinks that Seto is hitting it off with a female classmate, he feels a pain in his chest for some reason...?