My big sister, Ai Sayama, has seductive breasts so massive that they are all I can think about. Sensing my interest, she lets me touch her breasts as a reward for a massage, and my cock quickly becomes hard and large. Unable to hold back any longer, she pounces on me. I thought she was just a big sister, but her animal instincts are more than I imagined. This is the erotic story of a horny brat losing control and his big-breasted sister's runaway lust.