Note:  This was taken from 7chan's /elit/ board.  The original author went by the name Fluffins.

God I love Biology thought Hanna to herself as her slick cunt was pounded by no less than 12 inches of meat. she jerked herself off as well, facedown on the table, the little 14 year old girl had her ass up in the air, her sweet, wet pussy lips eagerly eating her best friend’s dick, and her own hand wrapped around her own pole while her nuts swung back and forth in rhythm with the slapping of Hazel’s thighs into her ass. Hazel moaned as her rod was sucked into Hanna’s tight little fuckhole, burning as her sagging ball sack dangled between her legs, filling with thick, creamy spunk in preparation for her upcoming orgasm.
The rest of the class was also hard at work fucking each other’s brains out. Jackson Brown and Larry Jones (the football team’s star athletes) had both undergone the full effects; both their cocks had majorly enhanced, and their bodies had grown tits and pussies (though Larry‘s were significantly bigger), Larry was busy sucking over half of Jackson’s cock in his slutty little mouth (everyone had known he was gay anyways), jerking himself off as Hilary White fucked him in the ass.
“You like that?“ she asked as she buried herself to the hilt in his little sphincter, she was grabbing his hair hard and shoving his head forward on Larry’s cock, “You want my cock deep in your little whore ass, huh?“ she giggled and began pumping harder, “You don’t even need this disgusting pussy, you just want it up your asshole you little faggot slut!“ He was such a little whore, and everyone knew it. He loved being spoken to like that, and Hilary loved saying it. As soon as the serum had taken effect, he had begged for cocks in his ass, which Hilary was happy to oblige.
Madison, Haley, and Shayna had cornered John, the reclusive nerd, and forced him to take the serum too. Before he even grew a pussy they had their cocks inside him as far as they could fit, though he seemed to warm up after the drug had taken full effect, and was now hard at work sucking off all three of them at once.
“Fuck me! Fuck me harder!” Yelled Emily ( the notorious class slut) from across the room while she rode Jorge’s newly-enhanced 2-footer up her ass cowgirl style, and Jorge’s newly-acquired pussy was fucked hard by Greg’s newly enhanced 17-inch rod, and Greg’s newly-acquired cunt was being ravaged by Miranda’s brand new 18-inch-long cock, all While Emily rammed her favorite footlong dildo up her whore cunt, screaming, “Oh fuck! Oh fuck yesss! Fuck my ass harder you little cunt! Fuck me! Fuck me! God FUCK someone get their cock in my goddamn fucking mouth!”
The remainder of the class was sort of whimpering in the corner, about five of them, three girls, two guys, who had adamantly refused to partake, and now watched in a combination of awe and terror as the class erupted into orgy around them. Hanna’s seat happened to be in the corner where they had decided to huddle, so while she was bent over the table, she was staring down into their faces. The two boys, the only two people left in the room without pussies or tits, were rock-solid under their pants, Hanna could see it plain as day, pitching tents through their khaki uniforms. The girls were similarly horny, the only people in the room without cocks, they were uncontrollably enthralled with the sight of the newly-formed dicks, none of them less than 12 inches, they were all bigger than any of the three still-fully-female members of the class had ever seen, many far more massive than they had ever imagined possible, and it showed in the small puddles of liquid forming between their legs. Hanna smiled at them as her cunt was ravaged by Hazel, Her moans an intoxicating siren song coaxing them to join in. For some reason, the five found it too terrifying or gross to partake, despite their obvious arousal.
Ms. Harrison, the class’s biology teacher, walked around, checking on all the groups to make sure they were working well. Her own 34 inch erection, as big around as a fire extinguisher, swung happily to and fro, her testicles the size and nearly the weight of bowling balls swinging between her legs, as she wore nothing but her lab coat. “How are you and Hanna doing?” asked Ms. Harrison as she approached the two friends, hard at work fucking over the lab table.
“w-we’re doing great, Ms. Huh-huh-Harrison!” Hazel panted over Hanna’s loud, ‘annnnhhhh~’ and ‘ooooouuuhhhhh’ moans, “this, nnnhhh~, is the best -- fuck! -- project all year! Mmnnnh~” Harrison reached a hand down to Hazel’s pert, pumping ass and grabbed a handful tight.
“seems the experiment hasn’t let you two down!” she smiled, cupping Hannah’s large nuts In her hand, squeezing gently as Hazel fucked harder than ever, “That’s a good girl~”
“thank you -- oh fuuuuck! -- Miss Harrison, Fuck yeah!” Hanna squealed in delight as her balls were fondled, “oh, my big, sore slut balls feel so good in your hands, miss Harrison!” she yelled loud, arching her back up, looking over her shoulder, auburn hair hanging, disheveled, over her shoulders as her cleavage was squeezed between her arms, “k-keep, keep t-t-touch-- Annnhhh!”
Miss Harrison reached her other hand over, slapping Hannah’s large, jiggly ass lightly, “mmn, what a fine specimen,” she smiled, grabbing and shaking the thick, soft flesh, “have we tested this out yet?” She asks Hazel, running her finger over Hanna’s tight, puckered, pink anus. Hazel only shook her head and kept pounding away at Hanna’s tight cunt, panting in short, gasping breaths, feeling her first male orgasm building, the pleasure was unlike anything Hazel had ever felt, She moaned loudly when she could catch her breath as her thrusts into Hanna’s womb became short and fast, slapping harder and louder. Miss Harrison took a pair of fingers and slid them gracefully into Hanna’s virgin ass, wiggling them lightly inside, probing at the soft, wet flesh inside Hanna’s ass.
Hanna screamed in ecstasy as her balls sucked up against her pelvis, her first ever male orgasm rocketing through her bowels and up through the thick tube in her cock. Huge, gooey torrents of cum splattered out of her rod, gallons pouring out with each time her cock pulsed, coating the floor in thick, gummy pools of semen, piling up in some areas where it was too thick to spread out, it splattered up her naked calves and thighs, all across the chair legs and the bottom of the table, Hanna let out mindless shrieks of pleasure, spittle flying from her mouth as her eyes rolled back into her head, her tight, burning cunt quivering and pulsing around Hazel’s pole, her back arched high as she leaned her head back, letting the bathtubful of semen pour out of her body, coating the scared students in the corner quite liberally from under the table, before finally subsiding to weaker, smaller pulsations, her cum finally dying to a trickle. She collapsed forward onto the table with her ass and cunt still being worked, she felt Hazel gearing up for her orgasm, “I’m gunna, g-gunna~” she moaned before her own balls fired down the chute of her cock, induced by Hanna’s orgasm. Hanna’s eyes went wide again as she felt the incredible torrent of thick, gooey, warm liquid empty inside of her, felt her body distending, stretching wide, she looked as if pregnant with the incredible load in her belly, she screamed as a second orgasm rocketed through her body, her cock again began dumping gallons and gallons of semen onto the floor, Hanna slowly passed out, riding the wave of her orgasms, and thinking one more time Godfuckingdammit, I love Biology.