Using his left hand to block his mouth from Karyn, Jon pointed his right index finger at her.
Lets start with something simple he thought.
"Give me those boobs and bra."
Suddenly Jon felt his center of mass shift, his t-shirt had tightened around his chest and had lifted up the bottom revealing his stomach.
Lowering his hands he grinned at Karyn, "Well?"
"Well what?" she asked confused, batting another strand of hair away from her face while watching Jon pull down the bottom of his shirt to cover his exposed stomach, revealing his now ample cleavage.
Jon looked down at his now weighty chest and could feel the redness in his face. "Well aren't you going to make a guess?"
Karyn furrowed her brow, "Nothing seems out of place" she started, crossing her arms and touching a finger to her chin, not noticing that she was unobstructed by the bountiful busom she posessed only moments ago. "I still have that stupid blonde hair, and you're still as distracted as ever by those boobs we accidentally wished onto you yesterday..."
Then like a lightbulb in her head she knew she had him, "Aha!" she pointed at Jon, like she'd just Sherlock'd the answer, "You swapped our clothes didn't you! That's why your shirt doesn't fit right!"
"BUZZZ" Jon imitated a gameshow buzzer, "Sorry Karyn, that's the wrong answer."
"But what else could it be! Nothing feels out of place!" she shouted, dumbfounded.
"Well you were close, I never made a wish about boobs yesterday, that was you." he smiled, watching the gears turn in her head. "I swapped our chests and I have your bra."
And just like that the penny dropped for Karyn, suddenly realising the relief for not having to carry around those unweildy orbs of flesh. "Woah, that is weird..." she gasped, patting her flat boyish chest.
Jon walked over to Karyn, though he was struggling to hide that the new sensations from the bouncing of his chest were arousing him, luckily it was offset by the uncomfort of the weight of them.
"Well you still have another chance," he said coyly, "ready for round two?"
He put his arm around Karyn, squashing the breasts up against her shoulder.
"You bet, you weirdo!" she laughed, shoving his buxom chest away.
"Alright then!" Jon laughed, turning to walk back across the room, quietly mumbling "You can have them back" and returning them to normal.