After losing her husband, Yuri Shirasaka enjoyed masturbating during the time her son was away at school. However, she made a critical mistake one day—after pleasuring herself, she fell asleep naked. Her son, a young boy at the age where he's just beginning to develop interest in the opposite sex, stumbled upon the scene and was overwhelmed by the intensely arousing sight. Shocked yet fascinated, he began to playfully tease his mother. Awakening to unexpected pleasure, Yuri didn't simply scold him—instead, she responded in ways she never anticipated.