bi no ossan, kousaka kyousuke, kousaka yoshino, tamura manami, ore no imouto ga konna ni kawaii wake ga nai, 1boy, 2girls, back, bare back, bare shoulders, bedroom, black hair, blue eyes, blush, brown eyes, brown hair, caught, door, fellatio, glasses, hetero, implied fellatio, mature female, mother and child, mother and son, multiple girls, opening door, oral, parent and child, ruining the glorious moment, short hair, sweat, sweatdrop, walk-in