How could Jon have ever believed that a body with breasts that size was beautiful, he thought. Now that he had such ponderous masses pulling at himself, he could never again think that... wait a minute!
Sarah had wished that he'd turn into his own image of the perfect woman.
She never said that he had to be a guy at the time it happened. Maybe he could do it when already a woman--maybe if his idea of the perfect woman changed he could transform again.
"I'll tell everyone about Sarah!" he thought. Or rather, she thought.
Suddenly her chest ached. It hurt like the devil, but it was a much smaller change than the female change and she found herself with normal-sized breasts. It works, she realized!
Jon concentrated and tried to imagine the perfect woman as having super-powers. Then she thought about telling people about Sarah. But nothing happened. Well, she thought, she knew it couldn't be that easy... but there would have to be a way. What was her idea of the perfect woman, anyway? There were a whole lot of different feelings she had... she wanted a woman to be feminine and sexy, but strong, but not dominating, but capable of handling herself, but willing to do what guys want, but... There were so many 'but's and half of them contradicted each other. Jon didn't honestly think a perfect woman is a woman with super-human powers, so she couldn't become that. But she didn't expect a woman to be a complete doormat and thought a woman should be able to take care of herself. Certainly she'd think an ideal woman could fight against other women.... And she was her own ideal woman now. She didn't even need to transform again.
Jon quickly went to her closet for some clothes. It turned out that she still had his guy clothes. Either Sarah had wished that reality doesn't change, or else if you wish a transformation rather than just wishing that someone be something, it doesn't change reality. But she was able to find enough gener-neutral clothes to fit her new frame, especially since she hadn't really changed height in going from a not-fully-grown teenage boy to an adult woman.
Jon didn't know how to find Sarah... she could be anywhere! Then, all of a sudden, he remembered Sarah's bright pink Porsche. She was the only girl with a Porsche and Jon had never figured out where she had gotten it from. (Little did she know Sarah had just wished it up, and her memories of Sarah having the Porsche were fake.) The Porsche stood out from half a mile away, and was a clear marker of exactly where to find her.
Jon quickly ran towards the water tower, imagining she'd have to climb it and look around, but she spotted the ugly pink vehicle down one cul-de-sac. Sarah was just driving around, not doing anything. (Jon, believing Sarah always had the Porsche, didn't realize Sarah was just having fun driving her new car around.)
Jon stood in the middle of the road and waited. Eventually, Sarah drove out and, noticing Jon in the middle of the road, got out and advanced on her.
"I told you to stay away from me," she said. "I told you I could do to you what I did to Karyn."
"You missed one thing," said Jon. "My ideal woman is certainly not someone who'd lose a fight to you." Jon ran towards her. "I wish," she said, at which point Jon kicked gravel in her face. She sputtered and Jon threw a punch at her, hitting her in the stomach. Then Jon kicked her with her new feminine legs. She hit Sarah in the arm and Sarah nearly dropped the stone.
Jon got behind Sarah and managed to do a chokehold. She was a grown woman now and could overpower Sarah. Sarah was able to choke out the rest of her wish. "... that Jon become as pregnant as Karyn, with a child that's half mine" before collapsing.
Jon took the stone but could feel herself transforming too. She wished that Sarah go home and forget about the stone, but that didn't stop her own transformation. She felt her stomach expanding, and labor pains beginning....