Weekend seduction

[T_B]

One day I saw my sister come out of the bathroom aftervher shower it was one of the rare days she forgot to bring in a change of clothes and was just wearing a towel I also saw dad watching her wanting her towel to fall off her 

I convinced him to let me take mom for the weekend and try to seduce her while dad stays here and try to seduce sister

First part of the story is a POV of the son as he seduces the mom the second part is a POV of the dad as he seduces his daughter with a optional third part with the son POV as the family ends up having an orgy 

The mom is a milf with D cup breasts and a shared pussy the sister has C cup breasts and a shared pussy 

If the orgy happens the mom and sister can get sexual with each other but the son and dad can't and the mom tells the dad that she prefers her sons dick but the sister also revealed that she prefers the dad's dick