Imouto to Sono Yuujin ga Ero Sugite Ore no Kokan ga Yabai (2016)

Miu's dislike of study has created a disaster, her math grades are falling sharply! Her brother, Kanata, receives the role of tutor from their mother in return for pocket money. Her best friend Riko is also invited to the study session! Riko is pretty with her brown hair in twin tails. In addition, she is well developed, with big tits… Riko likes Kanata, who is a good teacher. And Kanata cannot help but look at her bodily forms. Riko flirts and smiles, and always sticks close to Haruta while studying. Miu glares at her brother. Is she jealous? Kanata suddenly realizes, he is under pressure from both! What should he do?