Jon realized he had the rock in his other hand--now that all three of them had been merged into the same body, the combined body was holding the same rock that Katie was, and carefully said "I can fix this. But you two have to say and do nothing at all until I'm finished. Don't even ask me if we're finished. Is that okay?"
His body said "Okay", then it was like it was trying to say the same word again while already saying it.
Jon had to do this fast, because there was a good chance that Samantha (if not Katie too) would mess up a wish by saying something in the middle of the sentence.
"I wish that when the last wish made us Katie's little sister, it gave us separate bodies like Katie's sister rather than combining us."
Suddenly, Jon was holding the rock, and had complete control over his body. At the cost of... Well, he was still a ten year old girl. And standing in front of him were two other ten year old girls in identical clothes.
