When I removed the rubber band and inserted it raw, my sister suddenly changed! My sister, who is taking the entrance exam for a super-difficult university, is devoting every minute of her studies to her studies. My older sister, who dedicates all her time to her studies, is not into love affairs, and since she doesn't masturbate, she always calls her younger brother, me, to put on a rubber band and insert him into her to dispose of her accumulated sexual desires.