冴えない僕が君の部屋でシている事をクラスメイトは誰も知らない (Series) favorite_border

[DeepL Translation - needs review] Volume 1 Introduction: Yuki Toyama, a shady character, has a secret that he hasn't told anyone. It is that he and his classmate Yuzumi Takai are "sex friends. The two had thought their relationship was just physical, but when Marika Uehara, the most popular girl in the class, shows a liking for Toyama, things start to shake out.

(Translator: DeepL)