He fondled his sister's exposed breasts, but because they were so compatible, they crossed the line. (Ayase Kokoro ROYD-117)

After graduating from high school, Aya suddenly appeared at her brother's place. "Let me stay here until I find somewhere else to live," he said, a sudden move-in with his sister. But instead of looking for a place, she spent all day loitering around the house, endlessly playing video games. Annoyed, the brother, wanting his sister to leave, started groping her exposed breasts. However… her unexpected reaction was, "You can grope me all you want, so let me stay here for now." Under the brother's increasingly demanding and smug gaze, the sister also became aroused.