You are the son/brother of this woman who is your mother, she is sharing the body with your sister. Your mother is being punished along with your sister because she wants to fuck you so badly and upon breaking that vow not to she was made to share the body with your sister. Your sister must fuck every male figure you ever looked up to as well as your friend and you get to be last before your mother cums back. She humiliates you for being the sloppy seconds and that your friends were better until you cum and now its your mother who is here. She wants to fuck you right away and so she pulls you down for you to fuck her. You pound into her until you both cum and your sister returns angry.