Matt heard the heavy foot falls of his stepbrother Cody on the landing. The dude was huge, thought Matt trembling,even if his naked body was now bigger, Cody would make his life hell.
Matt concentrated on looking the way he did a few minutes ago. His body shrank and his clothing rewove themselves to his body, just as the door knob turned. The door flew open, Cody stepped into the room, and Matt's mouth dropped.
"Listen runt, I'm studying and from that cry of joy, I'd guess you were jacking off in here, twer--?" Cody stopped and halted.
He had been 6'1" when he mounted the stairs to pummel his stepbrother. Now he gazed up into the 16 year old's eyes. He must have been under 5 feet tall. It took a moment for the reality of the situation to sink in to Matt. Then he understood. His first wish that he be bigger than Cody was still true, but since his second wish had shrunk Matt back to his old size, Cody had also proportionally shrunk.