Her husband is only good at being serious, and she's not satisfied... so the younger sister of a playboy couple complains to her older sister, who then proposes to swap husbands. Unable to refuse, the younger sister and her husband come to visit her older sister's house, and she accepts, and when they begin to seduce her older sister's husband... the older sister is confused and jealous by the unfamiliar appearance of her husband. Then, as her younger sister's husband attacks her, she begins to feel aroused by the forceful way he embraces her, which is different from how he embraces her husband... The guilt and pleasure of being embraced by another man in front of her husband makes her writhe in pleasure, and she climaxes, accepting the other man's cock and sperm!