Based on the erotic game by G.J?.

Shindo Nikita has a secret that he has been hiding for a long time—he loves hentai and h-games. He enters "The Alternative Trivia Research Club" where the first of his many sexual encounters takes place. Despite that, he finds out that both of his foster sisters are in love with him, and he has to make a choice—who does he really love?

(Source: Anime News Network)