Karyn had wished that the rootbeer was a disease that she had beat, and the stone had made her beat it by having it run its course and giving her the condition permanently.
So now she had the condition permanently, which seemed even worse. But it wasn't. Because the first time, she had wished her breasts were filling with rootbeer. She couldn't just wish they weren't, because she'd be reversing a wish. But this time, she had wished to beat the disease. So all she couldn't reverse was beating the disease. She could reverse the part about getting a permanent effect--she just had to make sure the wish still came true in some other way.
"I wish that I beat the Sodajerk virus by it running its course and leaving no lasting effects, and that it affected nobody else because the disease has a low infection rate and everyone got lucky."
And finally, her breasts were normal, with no changes except the original wished-for enlargement. No, wait, the original enlargement and the false-pregnancy enlargement. Since her breasts were the same size as Joan's, she wondered if Joan had gotten the false pregnancy too, or if it was even false at all, if Joan got a copy of her body but not her ongoing magical effects.
"It's finally over" said Joan. "You know, I sort of miss the rootbeer. It was so surreal."
"Well, that can be fixed" said Karyn.
"No, wait!"
"I wish" said Karyn, that I can make anything I want fill and come out of my breasts without causing any pain or damage, but that it only works when I want it to and I can stop it at will. I also wish Joan can do the same thing to herself and Joan and I can do it to each other, but only the person who starts it can stop it."
"That's not as bad as I expected" said Joan. "I thought you were going to do something really dangerous. But I still don't want to be a drinking fountain."
"Don't worry!" said Karyn. Then she concentrated and Joan felt a strange feeling in his breasts, like they were filling up again....
