Ryuji and Masami are both friends with Shirou. Masami gets nervous of the way Ryuji looks at Shirou so he tries to warn Ryuji away from him. Ryuji proposes that since they both like Shirou but can't touch him that they satisfy their needs with each other. It's SUPER obvious that Ryuji liked Masami the whole time but it never occurred to Masami that the one Ryuji was looking at the whole time was him and he was desperate to claim him. A pretty good story, for the most part.
Renai Kyoutei Nukegake Nashi!