Jeff found a baggy pair of gym shorts in his room and squeezed his thick legs into them. They actually fit pretty well. He made his best effort to clean the jizz off his bedroom mirror. He smiled at his reflection one last time, then bounded to the front door and made sure it was unlocked. He returned to his room and texted Danny to come straight up to his room.
Waiting patiently for a few more minutes, Jeff found himself absentmindedly caressing his nice, soft stomach. Soon Danny would enter and see something completely bizarre.
After a moment, he heard Danny at the front door. He came up the front stairs and knocked at Jeff's bedroom door. Nervously he cracked it open. "Don't freak out. Promise me you won't make a sound," Jeff whispered.
"What's wrong with your voice?" Danny whispered.
Jeff flung the door open, still shirtless and barefooted, and let Danny take a look at his new body. "Nothing! What's wrong with yours?" he grinned.
Danny was speechless. Jeff beckoned him in.
"This is the Chronivac. It can change anyone's body into anything."
"You've gotta be freaking kidding me." Danny looked at the machine, and back at his twin. "That's really you, Jeff?" Jeff nodded. "Why are you me? Why are you naked?"
The fake Danny chuckled. "I couldn't fit your fat gut into any of my shirts, dummy. You wanna try this or not?"
Danny stared at the machine in awe. Then he looked back at Jeff. "Why are you wet? Did you just take a shower?"
Jeff thought of making an excuse, then realized it didn't matter. He had a feeling this wouldn't be the last time they got naked around each other, assuming Danny was on the same page as him. "Yup. You gotta problem with that?"
"So this thing, like, gave you my dick and everything?"
"All of it," said Jeff, still grinning. He reached his hand down his shorts and grabbed his balls just to prove his point.
"This is too weird."
Danny pondered the machine for a moment. "So it can change me into anybody?"
"That's the best part. You can literally change into anything. It doesn't have to be another person. I can make you seven feet tall, I can make you a baby, I can make you a dog."
"Just once? Can we change back after?"
Jeff rolled his eyes. "You think I wanna be an ugly little ball of marshmallow for the rest of my life? I'm just trying it out. Soon as you take your turn I'll change into something else. But you have to go first." Jeff felt weirdly uncomfortable making fun of his friend's body like that. Somehow it hurt his own pride a little, as he had started to feel like this body was a good home for him. But he had to keep up appearances for now.
He turned the screen back on and glared back at his twin.
"Danny! Hurry up and choose!"