The Reason I Have a Harem of Friends with Benefits

Lina challenges the introverted boy Nanase Nameless to refrain from masturbating until their next meeting. One day, when he reaches his limit, Lina says to him, "Let me do it now," and his heart skips a beat. Lina, Megu, and Mio—a group of four in tracksuits—get things started, and Nanase's excitement hits its peak! But just then, the busty teacher "Yuka" arrives, and the four panic and hide in a locker... Peeking at the girls changing in the locker room, like being on a crowded train, together with the girls in tracksuits!