Jeff decided he wanted to go a bit more into his role. He was to be seen as a milking cow for the most part, but unless he needed to be milked, most people ignored him so he could do as he pleased. However he didn't want to just be a human with an udder, that would be boring, so he had another idea, to change himself to both fit his role, and to be a bit more like a cow.
He would change it so his digestive system functioned like a cow's did for the most part. Most waste with turned into poop that he can't directly control the release of and the rest became milk for his udder. That was all he needed for his function beyond being able to eat grass and other things cow's ate, which he also included.
But then came the fun changes, so that he was a bit more like a cow. He would give himself a tail and replace his ears with cow ears. He would also remove his nipples since he had an udder. And instead of normal feet he would have hooves. It wasn't much but it would work for now as he set the changes to activate.
Sitting down on the floor again Jeff spread his legs, smiling as he looked at his feet. Which slowly melded into two black blobs before splitting into two toed hooves. Internalled Jeff had already changed as his tail grew out behind him, tapping against the carpet as his ears grew out and started flicking around at different sounds, finishing his changes.
And now, as he got up, he was ready to be the cow reality thought he was.