"Shall I help you practice kissing a guy properly, big sister? ///" My younger sister, who's been back from Tokyo for a while, is much more outgoing than me—and I've always been a little envious of her. "Hey, big sister, do you have a boyfriend??" "Wow, big sister, you have big boobs, and if you changed your makeup, you'd be super popular." My shy and reserved older sister, Hina, struggles to even talk to men, let alone have a romantic relationship...