You (Chris) and your brother Dick confront your sister on her time with dad, she admits that she is a free use slut for him and the family and you may as well join in. She uses her pussy and ass in front of you stuffing a plug into her ass after fingering it and tasting it before she slowly starts to fist herself to show how free use she is. She than convinces you and your brother to join in the fun. You fuck her, She sucks off Dick before taking him inside too until you are both used up and she goes to find daddy again...well she pees on the floor on the way out of course, just like grandma taught her