Jon said "I wish that everything was back to normal, and I mean what I have in mind as normal when I'm making this wish." He didn't want the wish to make things "normal" in some funny way, after all.
He needn't have bothered. The stone always gave an indication that the wish had come true. The sensation of not being able to look directly ahead. But nothing of the sort happened.
How can I make things normal when I wished for it to be interesting? he realized. I can't. The stone won't let me reverse a wish....
But then it occurred to him: he did wish for something interesting, but he hadn't said what would be interesting. Back when he and Karyn were using the stone on tree branches, he proved that the stone can interpret something in a new way. The branch still had to be blue, but it could be a different blue.
And things still had to be interesting, but maybe they could be a different kind of interesting.
So he could wish away parts of the new reality, as long as the whole thing, taken together, was still interesting. Or he could change them.
"I wish that my power to change things in a sexy way when I'm aroused, doesn't work on my relatives unless I want it to." That seemed like a safe bet.
There came the usual sensation of making a wish, and Jon put the stone in his pocket and exited the room. Things didn't seem to have changed. He saw his father, who seemed normal this time. At least he wasn't a scantily dressed blonde shemale. Since the stone changed reality, not only did he control the power, he always had controlled the power all the way back to the moment when he got it. So all the past transformations that got a little too incestuous would be gone as if they had never happened.
But this wish was just a test. The general idea of the power was, indeed, interesting, even amusing. Jon decided he'd keep it for now, and make some more changes. "I wish...."