He wished that they were both 6-year-old kids.
Immediately, they began to shrink as their bodies passed backwards through puberty. Mei's breasts flattened and her curves disappeared as all of Ty's body hair and muscle mass disappeared. Soon, they were nothing but a couple of naked 6-year-old kids.
As soon as they had transformed, Ty said in his high little kid voice, "Quick, get off of the bed. I'm going to change the room now."
The naked children stood back as Ty wished in his head for a room fit for two 6-year-old kids.
The bed split in half into a pair of twin beds, and all of the furniture was replaced by colorful kids furniture. All around them the floor became covered with toys. On Ty's side of the room there were mainly boys toys like cars and kiddie sports toys. On Mei's side there were mainly dolls including a giant doll house. Mei ran over to examine her toys.
"It's wonderful!" said Mei looking every bit the wide-eyed child that she had become. "Everything is perfect!"
Ty wished for them to be wearing pajamas. A pair of bright blue elastic pajamas with a cartoon character on the front of the shirt appeared on his body. Mei now wore similar pajamas except that hers were pink.
Next, Ty wished that everyone except them thought that all of the changes he had made were how things normally were. Just then, they heard a knock at the door.
Ty and Mei both turned to look as their mother opened the door and said, "Okay now, you two. It's time for bed. You both have kindergarten tomorrow."
Ty and Mei happily jumped into their new little beds and crawled under the sheets. Their mother tucked them both in and gave them each a kiss on the forehead. She then turned out all the lights, except, of course, for the night light.
"Good night," she said. "Sleep tight."
Then, she closed the door and left them to sleep.
Ty looked over at Mei, and the two little kids smiled at each other.
"This is so much fun," she said quietly.
"Yeah, I know," said Ty. "Let's play with our toys a little before we sleep."
"Okay!" said Mei excitedly.
"But be quiet," said Ty. "We don't want Mom or Dad to hear us."
They climbed out of their beds and headed for their toys.