Married Woman Group Pleasure Party: Forbidden Swapping

人妻集団快楽パーティー 禁断のスワッピング

Also known as Hitodzuma shūdan kairaku pātī kindan no suwappingu, 人妻13人いんらん比べ, 多情妻10人集団夫婦交際, 人妻(秘)淫乱パーティー　13人すけべ比べ, 人妻13人乱交パーティー

Three years have passed since Sonoyama married Akiko. Akiko was a virgin, but she was trained by Sonoyama and has now become a ripe woman. Sonoyama has a strong sexual desire and has another mistress named Michiko. One night, he goes to a swapping party at Michiko's urging, and they exchange partners and indulge in an affair, pretending to be married. However, a year later, the couple moves in next door...