Give me an extended plot of a novel. A woman have an aggressive big dog, who always has his penis in full erection everytimes the woman’s younger sister is around. Looking a way to tame her agressive dog, the woman wants to give it a shot to her dog’s excitement with her sister. So she once drugs her sister with sleeping pills and let her dog have his way with her sister. The dog is very excited about the mating, and ends up very 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 mating 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 pleasure and orgasms as the dog happily fulfilled his needs with her. The unbelievable happens, she will bear and give birth to adorable healthy puppies. She will loves them motherly, and finally coming to terms with the pleasure of her matings with the dog, with all puppies-bearings, and with her role as the dog's mate, who she likes more and more as he becomes a lovely lover and partner in life. The woman has no remors or guilt, she's happy for having now a nice dog and a happy sister. Secret affair - stay between the sisters. No supernatural, magic nor mythical. Set in the real of 2022.