The next morning, Mei woke up to the sensation of hanging from her own hair. She didn't feel any pain from it. Her body was light enough and her hair strong enough that she could hang like that somewhat comfortably. Still, hanging like that was just another reminder of how helpless she had become, which was only underlined by seeing who was holding her.
"Wakey wakey," said Ty with a malicious grin.
"Ty," she said. "Please, turn me back. I'm sorry!" Her tiny voice sounded so pitiful.
Ty pulled her closer to his face. He seemed so big now. "And just why should I? So you can be a jerk again?"
"No," she said. "I promise I'll be nice. Honestly!"
Ty seemed to consider the idea. "I dunno."
"Please, please, please, make me normal. I'm your sister, Ty. I promise I'll be a better sister if you turn me back."
"Hmm," he said, and she held her breath. "What if I don't want a sister anymore, huh? What if I'm tired of being someone's brother?"
She just stared at him, her eyes pleading for release.
"Oh, alright," he said and then unceremoniously dropped her on the floor. Her porcelain body hit the rug with a hollow thump. Ty glared at her as she struggled back to her feet. "I'll make you human again, but you don't get to be my age anymore."
Ty closed his eyes and concentrated. Mei felt her body tingle and start to grow. The stiffness in her joints faded and she felt her skin become soft again. Soon, she was nearly three feet tall, but there her growth stopped. Happily she was human again, but now she was much younger. Her dress was the same style from when she was a doll, pink and frilly, but now she felt the added weight of a diaper underneath it.
"There," said Ty. "You can be my baby sister for a while. If you're really good, I might just make you a bit older... maybe."
"How old am I?" she said, not at all surprised that she sounded like a baby now.
"Two," said Ty. "You're almost potty trained, but you'll have to work at it. That's part of your punishment for being mean. If you really try, you might just keep from pooping your diapers. I'll make sure there's a potty training seat for you in the bathroom."
Mei was less than thrilled to have to go through potty training again, but she felt too afraid to complain. "Okay," she said.
Ty closed his eyes and focused, and Mei's bed was replaced by a crib with a unicorn mobile above it. Her toys vanished to be replaced by simple baby toys.
Ty walked up close to her, emphasizing his new stature in comparison to her. "You promised," he said. "You promised to be good. I'll be watching."
She cowered beneath him. "I will," she peeped, subserviently. "I will be good."
Ty smiled with wicked intent. "Good," he said and closed his eyes. "Enjoy your first diaper change."
"What?" she said, but she felt her answer between her legs. A spreading warm dampness was weighing down her diaper. "Did you just-?"
"Yes," said Ty, grinning. "I made you do it."
Mei was furious at him, but she had to control herself. She took a breath and said, "Okay, I'll call mommy."
Ty stepped aside and gestured towards the door of the room. "Have fun," he said.
She toddled past him, and tried not to let on how angry and frustrated she felt. She would put up with it for now, but She hoped that Ty would let her grow up again soon before she lost her temper.
"Mommy," she called, and waited to be changed.
***
After it was all over and she was once again powdered and wrapped back into a dry diaper, Mei tried to forget the humiliating experience.
Ty showed some mercy and sat to play with her for a while with her blocks. Though, he took one of his race cars and knocked down a building she had just built. She could sense Ty appraising her carefully, trying to see how she'd react, but she held herself together and did not shout or cry.
Seeing that he needed to intensify his provocations, Ty then pushed her over on her back, startling her. His fingers played around on her tummy, and she started to giggle at being tickled.
"Who's a cute baby?" said Ty in a cutesy voice. She covered her belly, and he tickled her under her chin for a moment then back at her tummy when she tried to cover her neck. There was no escape.
Between giggles, she stuttered, "S-Stop it, T-Ty." She may have been laughing, but the tickling was starting to feel like torture. Her arms and legs flailed and tried to protect herself, but she was trapped.
Ignoring her pleading, he asked again, "Who's a cute baby girl?"
"T-Ty!"
"Are you going to get mean now?" said Ty, glaring at her seriously.
"N-no."
Ty said plainly, "Who's a cute baby?"
Tears had formed in her eyes. She was desperate to escape. "M-Me," she said between chuckles, feeling mortified. "I'm... a c-cute baby."
Satisfied at her surrender, Ty stopped tickling and stepped away. She was free. Mei wiped her eyes dry and caught her breath. She hoped that she'd passed his test. Sensing the dryness between her legs, she was thankful that she had just been changed. That tickling would have made her mess her diaper if she had to go.
Ty looked at her carefully. Again, she could feel him appraising her. "So," he said. "Do you think you learned your lesson?"
She sat up. "Yes," she said, hopefully. "I'll be good. I'll listen and be good to you."
Ty thought about her a moment and then nodded his head. "Alright then," he said. "One more test."
"What is it?" she asked, expectantly.
"Just wait," he said.
***
The day passed slowly. She tried to play with her toys, but she had a hard time enjoying them. Her mind still thought like a 6 year old's. Baby toys were just boring to her. At lunch time, she was strapped into a high chair and fed cut up bits of hot dog and green beans, not a good combo. She washed away the flavor with a big sippy cup of apple juice. She tried to ignore Ty as he ate his hot dog and watched her carefully.
A short time later, she was at her blocks again, and again she noticed Ty watching her. She knew that the last test was coming, but she couldn't figure out what it would be. He had refused to answer her before when she had asked about it, and she was too worried about upsetting him to ask again. She would just have to be ready for anything.
As she played, she felt a pressure in her abdomen. She had to pee. She stood up carefully and held her hands over her crotch to keep from leaking. She noticed Ty staring at her intently.
"I hope you make it in time," Ty said and smiled.
It hit her. This was the test. She had to make it to the bathroom and prove that she was potty trained.
She started off to the bathroom, but she felt herself ready to leak with each wobbly step. She had to make it. If she didn't, who knows how long she would be stuck like this?
Ten feet to go, and the pressure was unbearable. She couldn't hold it. She had to hold it.
Five feet. Got to make it!
She reached the potty and then...