Bigger And Smaller

Sarah grabs the rock, causing John to freeze with fear of what her next wish will be. Luckily for him, Sarah recognized the fear was powerful enough and merely threatened him.
"Don't try anything like that again, or you'll regret it." She said, looking rediculously voluptuous and wearing only tight pink panties that were meant for her 16 year old body. Even she didn't have the rock, John would have done anything she asked.
"Ok, ok. Hand me the stone and I'll undoe your wish," John said.
"I'm not an idiot, John!" She shouted.
It was worth a shot, thought John to himself. "Okay, well what were the exact words of your other wish?" John offered.
"I don't know exactly... I think I just said, 'I wish my breasts were a lot bigger.'"
Maybe Sarah wasn't an idiot, but she wasn't exactly bright.
With her new wish, her breasts swelled up to double their already enormous size. They were now as big as soccer balls and hung on her perfect body.
She was furious. "You tricked me!" She shouted at John, holding the stone up trying to think of a punishment for him.
"No!" shouted John, covering his face as he was sprawled on the floor in front of her, unable to stand with his hurt leg. Looking up, he could barely still see her face through the cleavage in front of it.
"Tell me what to do, right now, to fix this or I'll turn you into... a frog," she shouted, not quite original enough to come up a perfect punisment.
"You can't undo wishes!" John blurted out, "You may be stuck like that!"
"Wrong answer, John!" Sarah shouted, "I wish..."
"Wait! Um... Try wishing you were always like that! Then maybe it'll let you undo it, because it won't have been a wish in the first place!" John said quickly. It really didn't make any sense to him, but he watched as Sarah puzzled over it for a second.
"Alright. I wish I had always been like this," Sarah said.
Nothing seemed to happen.
"Now I can shrink them down?" she asked John.
"Uh, yeah." He had no idea, and winced as she started to speak her wish.
"I wish I was smaller! Much, much smaller!"...