It was cold. Freezing. Below zero. Frosty, chilly, unbrrable. Excuse the pun. But, as was said, it was cold at Hogwarts school for Witchcraft and Wizardry. So cold, in fact, that a certain student was willing to break the rules to warm up…

Hermione Granger hadn't been this cold since, well, since ever! She had lived in a very cozy, very warm neighborhood, where even the rain felt more like a nice shower than a heavy downpour. Her only memories of winter were around fireplaces, wrapped in blanket after blanket, sipping eagerly at her hot cocoa in search of marshmallows. But at Hogwarts, the winters were far removed than the ones she knew. Snow piled on top of itself, surrounding the school grounds. Layers of clothing weren't just recommended, they were required, unless a student had a tendency for frostbite. The wind pierced at children's ears, stinging them and turning them red.

But Hermione knew exactly how she could warm herself up. And, while not as simple as a school encompassing heat charm, it would be far more worth it. After all, what wasn't worth sweating over? As Hermione prepared the final ingredient, she heard the door to the closet she had tucked herself away in opening.

"Hey Hermione," came a familiar voice. "Ron and I just found a suspicious looking cat out in the hall!"

"Really Harry? That's very convenient for what I have here… Come, I'll show you!"

Harry, Ron, and their assortment of pets climbed into the closet, watching it expand as they went further in.

"Gotta love magic, don'cha?"

"I'll second that, mate."

Hermione beckoned the boys, waving them over to her cauldron.

"Alright, Harry, Ron, here we have a batch of-"

"Polyjuice Potion!" Ron blurted out. "I'd recognize that smell anywhere."

"Mm, yes. Well, as you know it is beyond freezing here, so I've devised a way for us to… warm up, as it were."

"What, are you going to make us fat?"

"That was my original intent. However, my fat fetish is second only to-"

"Let me guess," said a resigned Harry. "Furries?"

"How did you know?"

"Because wanted us to bring in this random cat."

"Maybe I just really like cats," said a defensive Hermione.

"Yeah," Ron chuckled, nudging Harry. "I bet she does."

"Only when they're fursonas!"

"Mmhm."

"Oh my- What is wrong with you two? Furry culture is so much more complex and interesting than people in fox costumes slapping each other's dicks!"

"Whatever you say."

"You two are horrible. Just give me a hair from one of the cats and we can get started."

Harry, stifling a laugh, plucked a hair from a bright orange tabby, and gave it to Hermione.

"Thank you, for actually cooperating."

Hermione dropped the hair into her cauldron, causing the potion to bubble and turn a deep shade of green.

"Hermione, get the thing away from me," Ron moaned, his face turning the same color as the potion, "or I will barf."

Hermione moved the cauldron to the side, and reached for her ladle.

"Now, all we need to do is drink."

"We!?" Ron and Harry shouted together, horrified. "You didn't say anything about us drinking it!"

"Why do you think I wanted you in here? Besides, furry sex is so much more rewarding than simply masturbating."

"I dunno, I could actually get into this," said Ron, shrugging his shoulders.

"No! No, mate, she's getting to you!" Harry yelled, shaking his friend. "You can't give in!"

Hermione only smiled, and drank down her ladle full of Polyjuice Potion. Shortly afterwards, she doubled over, clutching her stomach. What strength she had was used in ripping off her clothes, leaving her bare for Ron and Harry to witness. First, Hermione's breaths enlarged to incredible proportions. As they swelled, Hermione started rubbing them with a furious passion, forcing milk to spill out of her pert nipples, which had hardened enough to cut diamond. Orange fur climbed out of Hermione's skin, covering her in a warm coat. She licked her lips as she felt her crotch tighten and expand, a 12-inch cock erupted from between her legs, throbbing and veiny. Harry could only stare in horror, while Ron looked on intently. Hermione's hands and feet expanded, morphing into giant paws. Finally, Hermione herself grew to be 7 feet tall, towering each of the boys.

"Now," she said, voice now husky and flirtatious, "who wants to go first?"

Ron's hand shot up immediately, and he let himself be picked up by the furry in front of him.

"Hermione-"

"No Ron, you can call me Furmione now. Either that, or Mistress."

"Mistress Furmione, do I need to take off my clothes?"

"Oh no, you just need to relax that juicy asshole of yours."

Ron let his anus open itself, only to be penetrated by Furmione's thick, throbbing cock. Her massive tool punctured Ron's pants, ripping them apart and delving straight into his now tight ass. Ron let out a long moan, of pleasure and pain.

"Think we can go deeper?" Furmione asked, whispering into Ron's ear.

"Please Mistress, I need more!"

Furmione placed her paws on Ron's hips, and guided his body down, pushing her cock further in. Ron's moans grew louder and louder, until he was screaming, begging for more. Ron's own member had grown massively, and continued to do so with each moan. Finally, he released his sticky fluids, spraying Harry in the process.

Harry felt the semen that had drenched his body, and was immediately enraptured by it. He rubbed Ron's seed across his body, licking up any that happened across his mouth. Soon, tufts of fur were growing out of Harry's skin. He took his robes off, and started to scratch at his fur like a man would his dog.

"Yes Harry, let it all out, soon you will no longer be troubled by the folly of man."

Harry began to grow as the fur began to overtake his body. His hands and feet morphed into giant paws, and soon enough, he was just as tall as Furmione, albeit with less boobs, and far more cock.

"Mmm," said Furmione, casting Ron aside to press herself against the newfound furry. "And who might you be?"

"Me?" Came a deep, creamy voice, like warm gravy over freshly cooked turkey. "You can call me Hairy Potter."

Soon the two furries were upon each other. Hairy reached for Furmione's gargantuan breasts, spreading them apart far enough to place his rock hard dick between the two beautiful mounds. Furmione moaned in pleasure as Hairy began to move his cock up and down, rubbing against her breasts. As he licked her nipples, Furmione's member began to grow, regaining its hardness. She reached for her dick, and leaned into Hairy's tight asshole, and began to lick it. Harry gasped at this newfound development, and began to tighten even further in pleasure. He clenched down on Furmione's tits, causing her immense pleasure and pain. Soon, both of their dicks were ready to burst, and so they let loose their mighty cannons. The furries' jizz splattered itself all over the walls, floor, and ceiling. As both lay on the ground, gasping for air, Furmione turned to Hairy.

"Hairy, you don't think that this gift should be wasted on just the two of us, do you? No, of course not. I say we bring Hogwarts the gift of the yiff."

"The gift of the yiff?"

"Yes, and I know just where to start…"

Furmione turned her gaze to Ron, and a smile slowly broke out across her face.