"I wish for all this, the wish being over when I say, um, 'wish over'. One guy I know will be a girl instead. The girl will look, act, and dress as much like her former male self as is possible without being a freak or the situation not making sense. She will have the same or a similar name and will keep most of her friends and interests. However, she will be attracted to guys and will expect her boyfriend to act how a typical girl would expect her boyfriend to act." Jon added the last clause because he didn't want someone who is gender-flipped to want her boyfriend to also act gender-flipped and wear skirts or something.
There were, of course, still ways that that wish could go wrong, but he had just proven that he could retroactively say the wish only worked for a day or whatever if it was really inconvenient.
"Wish over."
