One day, Sachiko witnesses her daughter having sex with her boyfriend. Suddenly, something in Kokoro stirs. While her daughter is away, she meets her boyfriend who came to pick up something he forgot... "I want to be alone with you, mom..." Her adolescent sexual desire explodes, revealing her big breasts and tempting body. Her J-cup breasts shake every time she is penetrated. No... I'll never cum...! That's what she thought, but she was made to cum so many times that it was embarrassing, and she betrayed her daughter and had sex with him.