Jen wanted to stay normal, but she also didn't want to change her mother nor her Mary, she could be just a maid, but Jen cared a lot with her well-being. So Jen chose to mix it into the dog's (Lucy) food.
As soon as Lucy ended eating, she ran outside and Jen, as if something had been controlling her body, ran after Lucy.
Once outside Lucy began to change. She became a human girl, but still had dog ears over her head, her tail was still swinging behind her, her hands and feet had fur and claws. But she also had an erect dog cock in her crotch.
"Lucy" Jen instinctively called her. Lucy went into Jen's direction on all four. She hadn't learned yet about her new body and jumped over Jen.
With her new bigger and heavier body, she ended up knocking Jen to the ground and falling sitting on Jen's chest, with her cock over Jen's face, dripping precum..