Hidoku Shite Kure

Yuki Tsukishiro is an honor student at his high school and a national judo champion admired by both his classmates and teachers alike.
But, he harbors a secret. A secret that Kei Arima, the ringleader of a band of delinquents one year younger than him, has become aware of.
One afternoon's series of events culminates in the nurse's office, when Yuki and Kei come face-to-face. As the door clicks shut behind them, Yuki's secret is poised to unfold.

(Source: Renta!)