If only I had told him better then... When her son caught her masturbating, Shiori(Shihori Akiyama) regretted accepting the erotic acts he demanded to keep quiet. After that, her son's desires became uncontrollable. He hungrily sucked on her breasts and gulped down her breast milk, demanding sex. Resigned to his situation, Shiori accepted on the condition that "only the tip". If it was just the tip, it wouldn't have crossed the forbidden line. That was Shiori's thinking.