Give me an extended plot of a novel. A woman have a very aggressive big dog, who always has his penis in full erection everytimes the woman’s younger sister is around. Looking a way to satisfy her aggressive dog, the woman wants to give it a shot. She once drugs her little sister with sleeping pills and let her dog have his way with her  sister. The dog is very horny about the mating and ends up happy and calm after releasing his potent seed into her fertile womb. Witnessing this good result on the dog’s behavior, the woman decides to make her sister the permanent mate of her dog. To do so, later, the woman uses evidence - photos of the first intercourse of her sister with the dog - to blackmail her sister into her dog’s mate. From this very day, the sister will have incessant matings with the big dog, and despite herself - feeling shameful - she’s soon experiences relentless sexual pleasure and orgasms as the dog happily fulfilled his needs with her. Unbelievable puppies-bearings. No break free. No supernatural, magic nor mythical. Set in the real of 2022.