I had been living alone in a dormitory near my school, but I recently returned to my parents' house. My parents and grandfather live there. After my grandmother passed away, my grandfather became bedridden, and my mother was caring for him. My grandfather would occasionally call my mother in an inaudible voice and have her take care of her daily needs. One night, I heard a strange voice coming from my grandfather's room. It sounded like a sweet woman's voice mixed with a growling voice. Curious, I quietly opened the sliding screen door. There I found my mother writhing in pleasure as my grandfather sucked on her breasts...