Instantly, Jon and Karyn were separate. Just two normal teenage girls standing there...
"Jon!" said Karyn.
"What's wrong--wait, my voice, my..." Jon's own body felt strange to him, especially on his chest and between his legs... "I'm a girl!"
"You shouldn't make such hasty wishes. Didn't you know that there are very slightly more women than men around, so being a woman is 'normal' and being a man isn't? And the way you worded that wish, I can think of things happening that are a lot worse than just changing sex. Jon, give me the stone, okay?"
Jon tossed the stone over to Karyn. Karyn immediately put it in her pocket.
"Wait," said Jon, "I thought you wanted the stone because you were going to wish me out of being a girl."
"You made me walk around with a rock in my pussy, you can stand a little discomfort for a while. I'll give it back at lunch tomorrow. In the meantime, you can think of some better wishes instead of being so hasty with them.
"I did not make you walk around with a rock in your pussy. It just had to touch me. You could have put it in your pocket and made a hole in your pocket big enough to touch me but not big enough for it to fall out."
"You just thought of that now. You didn't think of it when I needed it. See? Hasty."
"But what will I do going home and coming to class as a girl?"
"It's not so hard. I do it all the time. Besides, everyone will think that you always were a girl...."
