Yumiko was plagued by sexual harassment from her son. When he caught her masturbating, she accepted his request for sexual acts in exchange for hush money. Since then, her son has been demanding various acts, and the content of his acts has been escalating. Eventually, he has been driven to the brink of penetration. Yumiko desperately resists, saying that this is not acceptable, but her son will not stop. Finally, he proposes a special rule: "If it's just the tip, it doesn't count as sex."