Despite Jenny's insecurities, Jeff didn't mind her being petite, not at all. So, Jeff decided he could change Jenny's body in the complete other direction. It'd solve the clothing issue if Jenny could borrow clothes from his 12 year old sister.
With the Chronivac, he copied his sister's bodily measurement, and pasted them into Jenny's profile. He then pressed apply.
Meanwhile, Jenny was searching Jeff's mom's closet for something to cover herself with, but then she felt herself change.
Her enlarged bosom shrank down. As did her hips. At first she thought Jeff was changing her back to normal, but it soon became apparant she wasn't quite going back to normal. She felt her shoulders narrow and her whole body contract. She was becoming smaller all over. She grabbed what was left of her boobs as they continued shrinking until they were pert less than a handfull, and that was with her now tiny hands.
"Jeff? What did you do?" She yelled out. "Did you make me younger?"
"No! I'll tell you!" Jeff yelled back, then he ran towards his parents bedroom. He placed his hand on the handle.
"Don't open the door!" Jenny shrieked and covered herself. Even if this was his doing, it'd too embarrassing being seen naked like this.
Jeff stayed outside the door. "I didn't make you any younger. I just made you smaller, so now you can borrow my sister's clothes," he explained.
"I see" Jenny replied. She guessed that was a solution for her problem, but she didn't quite like it. She'd wanted to impress Jeff, really turn him on with a curvy body, but no way he would find her particularly sexy now. Why did Jeff choose this direction? Surely this wasn't his taste? Not judging by how Jeff was very not subtle whenever he ogled busty women. "Go back to you room," Jenny said. "So I can get to your sister's room without you seeing me naked."
"Sure. I am going back right now," Jeff said.
Jenny heard his footsteps moving away, and once the coast was clear, she stepped across the hallway to his sister's room.
She searched her wardrobe. She started with underwear. A pair of her panties fit nicely over her tiny rump. Her breasts were barely existant enough to justify a bra, but. She touched her nipple. They were still sensitive, maybe more so even. She'd need a bra to protect her nipples. She found one and put it on, a pink frilly one.
Then, she borrowed a pair of skinny jeans, which required incredibly thin legs, which she possesed. For her top, she searched a bit. A lot of the tops were a bit childish to her taste, and on the other hand, some were more on the "too sexy" side. Jeff's sister was at that age where she was about to enter teendom, and such was in the middle of the transition of leaving childhood, and trying hard to assert herself as not a child. Jenny found a white blouse which seemed suitable enough for her, and put it on.
She returned to Jeff's room. "Here I am," she announced.
"Wow. You look cute." Jeff said.
He stepped up from his chair, and it was immediately obvious to Jenny how small she'd become with Jeff towering over her. It felt embarrassing, yet also it was hot.
Jeff stared at his petite girlfriend and felt himself grow hard. He tried acting normal, looking a bit away. He didn't want to straight up reveal how much he was into her new look.