Chuuken Kunshu

Katou is a member of the high school swim club. Matsuoka has come to bring him lunch and use Katou as his stress relief punching bag yet again. To the sympathy of his club mates, impulsive Katou totally falls for him, saying with a shy smile that Matsuoka is cute… Even as Katou treats Matsuoka kindly and tells him that he loves him, Matsuoka remains a total tsundere, leaving doubts to linger in his heart!

(from Boys On Boys Love)