"Here we go" Mary said, popping the top off the cork and drinking the vial labelled "Female". She swallowed the sweet liquid, and then returned to the bathroom to watch her transformation. Just walking back she could feel herself beginning to change.
By the time she got to the bathroom, and stood in front of the mirror. The first notable change was to Mary's hips. They appeared wider, giving her very ample curves. Her flat chest started to tingle, and it wasn't long before Mary had A cup breasts. Furry breasts, but breasts. Mary wasn't about to complain about the fact that her body was still covered in donkey hair. In fact she kind of liked it. Her breasts continued to grow, pushing past B, then C, and finally stopping at a decent DD. Her nipples were very different though. Mary attributed it to her donkey nature. The skin of her nipples was black in color, and very thick. Touching it with hoof-hands, Mary felt a rush of pleasure. Her body was so sensitive now.
Mary felt another change hit her gut. Her cock rose, but it appeared to be smaller than she remembered it being. Still, the flared head stared back at her, and Mary had to do something about it. As she began stroking herself, the pain in her gut spiked. Then, it was as if her body exploded. Something popped open, and Mary felt another intense rush of pleasure.
She had her suspicions, but had to check to see if it was true. Her hoof-hands probed underneath her testicles until they touched squishy flesh. And then they slipped inside something. Mary bucked her hips backwards as she inadvertently started finger herself. Her vagina was back, and it was just as sensitive as her cock.
Mary turned around to see her pussy. It was clearly a donkey's organ. The skin was dark and thick, bulbous even. It Mary knew she'd easily take a donkey cock, or any other sized cock. She was huge. Her whole arm could probably fit in there. As she continued to massage her netherlips, her cock begged for some attention.
Unable to properly pleasure herself standing, Mary returned to her bedroom. She went to her closet, where she kept a secret stash of sex toys. She dug around until she found the one she desired. A dildo with a distinctly flared head, much like a horse's or donkey's. Mary licked her lips at the sight of its ten inch length, and flopped on the bed. She propped her legs up on the bedframe, and slide the dildo inside herself. She didn't even need lub, her lips were so swollen and ready to take a cock.
Mary moaned as she slide the cock inside her pussy. Her own cock smacked against her chest, hitting her tits and nipples in the process. Mary released a shrill "HAW!" and began thrusting the dildo in and out. All the while using her other hand to fondle her breasts and cock. It was a lot of work, stimulating every erogenous part of her body at once. She imagined that it was an actual donkey stallion doing the fucking.
Again, Mary's balls pulled up and then down as she came. Her orgasm went everywhere. Straight in to the air, and then it rained down on her and the bed. Her pussy clamped around the dildo, wetness spilling out of her. Mary cummed for a good ten minutes before she finally stopped. She lay on the bed for another ten minutes recovering, and thinking of ways she could feel a real donkey cock.