It's like this

Once they got to the parking lot and where sure no one was around, Janie(Jon) filled in both confused girls. Karyn stood by still huffing from the walk out.
'Janie, let's show them. I'm really tired of being this fat, you know." Karyn said.
'Okay,' replied Janie, leveling the remote at Karyn. Almost instantly, the blond, buxom Karyn from before was back, only decked out in ridiculously oversized clothes. As she shrank down, though, Janie's nose began to stretch again, evening out at two inches.
'Damn it! That's no good!' screamed Janie, stopping her boot and causing a mass of jiggles.
'Oops! I forgot about that...' murmured Karyn. 'Let's fix it. Gimme the remote.'
'Nah,' said Janie. 'Leave it for now. Just make me not so pregnant, please. Don't worry, my protection wish doesn't count against wishes I approve.'
'But you'll look like a freak!' Karyn said.
'It's okay, really,' said Janie, 'because remember were going to school like this and your going back to being Piggy-Sue here in a minute.'
'But...' Karyn moaned.
'I won't make you as fat this time, so long as I don't have to be pregnant,' Janie replied. 'But I am going to make you look a little more piggy...'
'Eh-Hem!' interrupted Chloe. 'You two are some definite weirdos, but we wanna play too! We've always been nerds, but since you two are going to be at school tomorrow, can we be the popular girls who pick on you?'
'Sure!' replied Karyn.
'I agree!' said Janie. 'This'll be fun.'