Mary felt a more animalistic side of her taking over. Her growing nostrils flaring, as she reached out her hand to her wet pussy, and she indulged herself. As she fingered herself, she felt waves of immense pleasure washing over her. She let out a soft whiney, as her body began to shake with excitement
As she began to thrust faster she could feel her coat of hair begin to spread over her entire body. With each thrust, she felt her body begin to grow even more with mass. Her butt expanded resembling more of a horse's hindquarters. Mary moaned, her face beginning to model a partial horse's muzzle, as it pushed out from her face. She could feel her pussy lips begin to widen and shift location as she continued to pleasure herself.
Another notable change began to develop, as Mary could feel her belly begin to barrel out. The feeling of becoming larger and thicker turned her on even more. With her free hand, she felt her plumping hairy ass and moaned again, feeling her butt continue to expand. Her tits weren't safe from the change either, as Mary marveled while her already large hairy breast began to bulge even further.
Mary couldn't take it. Her legs buckled and she found herself lying on her back. Panting now, she made a slight whiney as she was nearing her climax. As she climaxed, she let out a loud whiney, bursting with pleasure and relief.
She laid on her back for what seemed like a few minutes. Mary began rubbing her now almost hoof-like hands over her bloated body. "I guess I only stopped at part-horse because I didn't drink the whole vial."
Mary attempted to prop herself up but was met with some difficulty. Her large horse-like body was definitely much more massive than she would have liked to admit. Her horse belly gave a loud rumble, which surprised Mary. She giggled, licking her now larger horse-like lips.
"Guess it's time for a snack."