Five years ago, Shiori, who was a student, had a relationship with her cousin Masafumi due to a little impetus. She didn't have sex though, she just taught Masashi how to masturbate, who didn't even know how to do it. What were they doing at the time? Since then, Shiori has been feeling awkward and has kept her distance from him. Time passed, and the two were to meet again, but... Her cousin's monkey-like libido drives Shiori's body crazy!
