"I'll prove it," Jen said. "I want to be a boy." Suddenly, her breasts receded into her chest, a penis pushed itself out of her vagina, and her entire body returned to its previous male look. Jen had become Jon again.
"Nothing happened to you," Karyn said.
"What do you mean? I just turned back into guy."
"Jon, you already were a guy."
He looked at her, not understanding how she had forgotten the last few minutes, but then he began to realize that maybe him reversing his wish also reversed reality. Maybe he was the only one that remembered, because he heard his own wish.
Jon looked down at himself, making sure that he had really changed back to normal completely. He had, but as he did his inspection, he noticed that he was still wearing girl's clothes. Hey, why didn't my clothes ... he thought, before realizing what had happened. His eyes went wide. "I didn't give my last wish a limit."
"What are you talking about, Jon?"
"My clothing. I'm gonna be stuck wearing girl's clothes."
"Jon, you've always worn girl's clothes. At least as long as I can remember."
Oh god, Jon thought, gasping. Reality changed itself so that it's normal for me to wear girl's clothes. And I have no way to reverse the wish!