"First, you need to get naked for this experiment," the third year guy instructed. Mark looked nervously over to the girl by the white board. She was blushing too.
"This isn't a prank, is it?"
"No," the guy promiced. "Your clothes would get in the way." Frowning skeptically, Mark began to strip in the classroom.
The African American science student waved his Asian classmate over. She handed Mark something small, while trying not to look at his nudity. Though she kept steeling glances when she thought he wasn't looking.
It was a tiny skin colored full body suit of some strange and unknown material, no larger than an action figure. It felt like plastic, or maybe rubber or silicon? Mark couldn't tell.
"Put it on," the black student told Mark.
"Put it on? Is it super stretchy?" Mark tugged on the material. There was a tiny but of stretch to it, but it resisted deformation strongly. Also, there seemed to be no opening.
"Just put your foot in through the mouth opening there," the girl said. Mark looked and saw it opened at the mouth, eyes and two tiny holes for the nostrils. He doubted he could even get his pinky through that. But after some initial struggle, he got a firm grip on it and got in one, then two fingers.
Mark felt like he was going to rip the thing apart if he pulled anymore. The science student just looked at him expectantly. Here goes then. Mark pulled as hard as he could and got the opening just large enough from his foot and forced his toes in.
Something strange happened next. As his foot struggled to wiggle into the tight and tiny bodysuit, the suit seemed to be comptessing him instead of stretching. Mark's leg went in down to his thigh, but the suit's leg remained Barby sized. Mark wiggled his toes, and saw the tiny leg of the suit do the same. From the outside, it looked like he'd stretched the suit over an amputated stump.
"What is this!?"
"It's an inversely stretchy material we've created," the girl explained. "Instead of stretching to fit the wearer, it compresses the wearer to fit it. Now pleas, keep going."
Mark bit his lip and proceeded with the next leg. He got it in and managed to wiggled it up to his crotch. Or more accurately, he wiggled himself down to his crotch.
"Hey, um... I think there's something already im here. It's stiff and poking at my ass. And, it feels like my dick is being forced into a tight pocket that runs down between my legs?"
"That's just some equipment to monter the experiment," the large black guy dismissed bending down and tugging the suit sharply up and the object to slide fully into Mark's ass. Mark yelped. At first, the cylindrical object had been tiny and thin, but as his ass was shrunk down super small, the object grew huge and thick as it forced its way deep inside him. And his dick felt like it was compressed more than any other body part in the pocket between his thighs. It made his crotch look completely genderless, flat and smooth.
"Ah! Get it out! It's too big!"
"Easy, easy," the guy said. "You'll adjust. Take a deep breath." Mark did. The pain subsided, but it was still huge and invading inside his ass. "You're almost there."
The two students helped Mark get his armes in next. The suit was so tight that Mark could barely bend his limbs at all. And when it covered his chest, he struggled to breath, like he was wearing a corset. It strangled him as it tightened around his neck. He was just a head now, bobbing rediculously atop an action figure sized, sexless body.
They pulled the suits head up over Mark's face and soon Mark was completely encased in the suit. The suit covered him right to his lips and eyelids, only opening to his mouth, nostrils and eyes. No skin showed. He was a tiny toy figurine. He trained to move his armes to touch his face. His new mini-limbs were too weak to streach the material away from his face enough to escape it. He couldn't even get a finger in. It was so tight all over. He'd need the others help to get out.