"You like those big tits of yours? I wish you were flat chested," shouted Sarah.
Nothing happened. Sarah realized she couldn't undo the previous wish to make them bigger.
"Fine," she sneered, "Keep them. I wish you had do exactly as you're told."
Karyn was terrified, but at least there was a chance that orders that came indirectly from a wish could be undone.
"Clearly you're proud of your new body," said Sarah, "Take off your clothes. Show the world."
Karyn couldn't help herself as she stripped naked in the school hallway. It was empty at the moment except for herself and Sarah but any minute someone could come along.
"That's right," laughed Sarah, "You're gonna regret messing with me. You're a fucking bitch."