Tina saw the tail and new member on her sister and screamed. She tried for the door but slipped when her sister pounced on her, knocking her to all fours. Before she tried to get up and run before she made a startling realization, her sister was begining to mount her.
Fur errupted from her body at a rapid pace as her hands and as feet became paws, her finnal steps in becoming a retriever were completed. She finnally found her sister's love hole and shoved her newest anotomy into her sister's virgin body.
Tina screamed in pleasure and fear as she felt a sickening pressure building in her stomach. She felt humilated by not just being raped by a dog but by being fucked by her own sister.
Tina began to get real hot as she felt herself have her first orgasam. She moaned loudly as her tounge rolled out of her mouth. What scared her the most was that her tounge was not rolling back. She screamed a howl... as she saw hair growing across her arms. She felt her teeth sharpen with her new tounge and whinned as her hands and feet began to resemble paws. She then gritted her teeth as her tail pushed uneasily out her the top of her butt under the heavy weight of her sister's canine body.
Tina felt her sister finnally spurt her load into her body and she collapsed to the ground. She grunted as her finnal changes began, feeling relieved that the fuck was over. But, to her horror, her sister did not dismount so quickly as she tounged her body away from her Diane. Diane's instints became completely dog-like and bit Tina her loose-skinned neck and kept her from forcefully leaving her. Tina cried silently as she felt her body change.