Jane typed some commands in.
"What are you going to do to me?" Jeff asked, nervously.
"I'm going to make you a grown-up. You're going to go out and buy me some cigarettes and beer. When you're done, I'll change you back."
"Doesn't sound too bad, what's the catch?"
"I'm not just going to make you a few years older. I'm going to make you a big fat woman with huge boobs."
Jeff winced. "Why do I have to be a woman? Why do I have to be fat?"
Jane giggled. "It'll be fun, relax."
Jeff felt the transformation start. "Are my clothes going to change?"
"No, you better get those clothes off, you won't fit that fat ass in those jeans!"
Jeff groaned. He felt his body shifting and getting thicker all around, and felt his internal organs shifting, which made him a little queasy. His flat chest started to get sensitive and soft, his legs started to thicken, his butt filled up, and his genitals started to twist strangely.
"C'mon, Jeff! Get those clothes off!"
He reluctantly pulled his shirt off, exposing his weirdly shifting chest and belly. He unbuttoned his jeans and pulled them off, feeling creeped out at being half-naked in front of his little sister.
"What's it feel like?" Jane asked.
"It feels so weird!" His face was shifting, too, and even his voice.