Karyn has her way

He managed to reach the stone before Karyn did, but in his weakened state he took more effort to lift it, and Karyn was able to easily snatch it out of his hands.
"That wasn't very nice", she said, holding the stone over her head, just out of his reach. He was trying his hardest to reach it and came close a few times, which made Karyn come up with a new wish,
"I wish Jon was three feet tall exactly", Jon cried out for her to reconsider but it was too late, he could only watch in horror as the world outgrew him and he was standing in front what to him was a 12 foot giantess.
Karyn placed her hands on her knees and stood over Jon, still higher than him in this position.
"Now, THIS is just too cute!", she said as she placed the stone on a shelf well out of his reach and then threw him on the bed.
She took off her clothes and got on the bed on her hands and knees over him. Jon just looked up at her, amazed at her massive size and despite his fear, became incredibly aroused as her huge tits hung over him and he felt the heat coming from her pussy. She looked down at his cock and said,
"ooh, is that for me?" then lowered her head down to his crotch and took it in her mouth. Jon tensed up as waves of pleasure washed over him while Karyn placed his entire penis, balls and all, in her mouth. She gently swished them around and playfully batted it around with her tongue. Jon could only sit back and enjoy it, and became so lost in the moment, he forgot just how small and weak he now was. When he came, Karyn felt the warm liquid spary in her mouth and was glad there was less of it, she never enjoyed this part. She spit it out onto the floor and said to John,
"My turn now", as she lifted him up and rolled over onto his back. He crawled over to her huge wet pussy, and began thrusting into her with all his might. She just lay there, yawning.
"Is that all you can do? Oh yeah, I almost forgot how weak you are", she said then suggested he use something bigger. He asked what and she told him to use his arm. He made a fist and inserted it. He was shocked to see he could fit his arm in up to his elbow. He felt around and found her clit, which he grabbed with his hand and tried to massage. She felt it but he was still too weak. She had an idea, she pulled Jon out and retrieved the stone. She wanted to make this interesting so she said,
"I wish that unless Jon can lift my foot and hold it for 30 seconds, he would shrink to a size that would allow me to use him as a dildo".
She then went back to the bed and laid down.
"Get to work, little man", she ordered, "unless you want to give up".
Jon knew he was doomed but walked over to her foot anyway.
He bent down and took the large foot in both arms. It was two feet long to him and in his current condition felt like it weighed 100 pounds. He lifted with all his might, and managed to get it off the ground. Karyn began counting backward from 30. By the time she reached 25 he was shaking and on the verge of collapsing. When she hit 20 he lost his battle and the foot fell.
He shrank to 11 inches and Karyn's foot was now bigger than him. She gave him the choice of walking to her waiting pussy or being carried and he chose to walk. He arrived at his destination and she looked down and said, "Don't just stand there, hop in".