Omae ni Zettai Ienai Koto

Keigo is a super serious guy, and Shohei, the outgoing one. These two opposites have been best friends since high school and ended up attending the same university. Keigo, who's got a crush on Shohei, gets all twisted up about it and starts using toys to, well, pleasure himself while thinking about Shohei. On the other hand, Shohei gets some tips from an upperclassman about the wonders of self-love and ends up getting a prostate massager out of pure sexual curiosity. And guess who his material is... his best buddy Keigo!?

(Source: Takeshobo, translated)

Note: Includes the one shot “Mirai Travel x Virgin Revenge (ミライトラベル×ヴァージンリベンジ),” and an extra chapter.