Phantom mother - Forbidden mother and child swap Chaste parent and child vs lewd parent and child, sex-crazed double creampie sex

Eriko and Miki are beautiful sisters. However, Miki had a forbidden physical relationship with her real son Wataru. The two also wanted to attract Eriko's son to have fun together. One day, Miki seduces Kiyotaka, the son of her nephew Eriko, using her plump body as a weapon, and Wataru attacks Eriko. It then develops into an unprecedented mother-child swap.