Looking for a vintage Erotica book

[superbeastOR]

I remember finding this book one day when I was younger but I can't remember it's name. What I can remember is that it was a book about this teenage boy who had a girlfriend, but he would fuck his mother, and when his mom wasn't around his little sis would suck him. then if I remember correctly his little sis and his mom had sex, he also had plans to fuck his little sister because she had made him promise he would. Does any of that sound familiar to any one. If you know the name of the book I would be eternally grateful for the name. I know it was an older book I think the border was yellow or maybe the whole book was I don't recall to well.