Sister has to come home to take care of sixteen year old brother while mom is away. (I would say that this is somewhere between Much Sex and Some Sex.)
Bradley is an absolute pervert, and his family are fed up with it, especially his sister. Unfortunately for them, he's found a book that will switch his status with that of his sister's...
A story in the This Naked World Universe
Continuing on from the last story... Uncle Brady Goes to Night School... we have Jay Porter now turning sixteen and having some fun at home with his family then at school with his teacher then in the evening with his girlfriend.
He discovered his married sister having an affair with his best friend. Instead of being shamed or apologetic, she asked him for help finding someone who could impregnate her.
After my son left home his younger sister told me how he had raped her two years before. Once that secret was out, she continuted to tell me what he and she had been doing since then.