GVH-520 Her younger sister is a masochist, Yokomiya Nanaumi

She and I are college students. Her younger sister, 'Nanami,' is a high school girl. That Nanami looks docile but is actually a masochist... One day, Nanami noticed me watching her and started masturbating to seduce me. I was surprised, but decided to train this perverted sister of hers. Repeated masochistic training while she wasn't looking... The relationship between her and her sister escalated daily, ultimately reaching climax through bondage sex, becoming a complete masochistic female.＃YoroP