Option 2: Running a Train

Hermione was, obviously, the first of the pair to recover; she pulled her wand away from her suckling lips with a wet pop and a couple of quickly-snapping strings of spit, placing it on the seat between her and Rose as she stood up quickly enough to make her bust bounce in her woefully inadequate top and turned to face the new arrivals. "Hey there," she greeted them with a smile and a quick cup-and-jiggle of her tits to draw their eyes to her prices, "fancy a blowjob?" The one in front - who, now that she thought hard about it, she had a vague, hazy memory of - snorted and flicked his own wand, a more classical stick rather than the girls' dildos truncheons, at Rose. A small mote of pink light erupted from the tip, circled around her head a few times before darting downwards and under her skirt. The raven-haired young woman's hands immediately began clawing at the seat as her wand started pumping - hard and fast, naturally - into her of its own accord. "M-Malfoy! What did I tell you," she bit down a whine as the impromptu fucking machine's pace increased, "about using that bloody hex on m-me?"

"Do it as often as possible," the blon- no, Malfoy replied smoothly, "the more public, the better." Hermione made sure to commit the name to memory; she couldn't quite put her finger on it, but something about him was telling her that his cum must taste incredible.

"Thank God, you were paying attention," Rose grinned, before letting out a low, hoarse groan of pleasure as her animated wand twisted inside of her and ground the thick veins covering its surface against her walls. Hermione, sensing that she might have some competition once the other girl decided she'd rather have a real cock or six fucking her - and, honestly, getting hornier by the second just from Rose's sheer, infectious enthusiasm for the fake one already doing so - gave her hips a quick shake to draw the crowd's eyes back to her and tore open her shirt. Buttons popped off with enough **** that a couple went over Malfoy's shoulder and out into the corridor, the same enchantments that ensured her uniform top hugged her figure perfectly and slowly repaired it whenever it was off her body also working to enhance her sudden stripping.

"Like the merchandise, boys?" Hermione wasn't sure how she was able to put on such a teasing tone, given that she'd never even tired before, but something about advertising herself like this made it... well, it made it almost second nature! Her tits might not have been as huge as Rose's, but they were still more than enough to overspill from her woefully-inadequate - apparently intentionally so, given that her friend's was bigger, but seemed equally incapable of containing her chest - uniform bra, especially when she sank her fingers into them for a nice, firm squeeze. The looks she was getting sent a tingle through her body just as intense as the one she got from groping herself, so much so that she nearly didn't catch the small, square object that Malfoy fished out of his pocket and threw at her. "Well, you're certainly... certainly... oh, wow," she trailed off as she opened up the wallet and found that, not only was it bigger on the inside, it was stuffed to the brim with large, ever-so-shiny gold coins.

Slipping one hand into the mass and wiggling it around to find where the insides of the wallet actually were, she shot Malfoy a smoky - she hoped - look and licked her lips. "Well, I'd say..." she paused for a second to mentally hash out the amount that was probably contained, then did a quick headcount, "...that this entitles all of you to a full service. I'm all yours until your balls are drained, boys." And she was glad for it, too - it would have been a shame if she'd had to drop it down to oral only because they were underpaying, even just a little. I may be a whore, she thought, but I'm not about to start handing out group discounts, even for a dozen people! She strutted up to Malfoy and rested a hand on his shoulder, as the other reached down to stroke the bulge running down one leg of his trousers.

"Pick a hole, any hole," she smirked, before the tip of his wand tapped against her forehead and her body smoothly dropped into a floor-brushing, spread-legged skanksquat in front of him, fingers laced together behind her head as his trousers sprang open and a cock that her slightly confused brain compared favourably to her forearm slapped down heavily on her face. She opened her mouth and let her tongue loll out like the proverbial welcome mat, moaning happily as he rewarded her for her initiative by grabbing the base of his rapidly-hardening dick and guiding it into her mouth far enough to prod the back of her throat and make her gag noisily, even as her eyes flicked up to look at his face without any hint of discomfort.

“Good to see you’re as sloppy as you should be,” he smirked, resting one hand on her head and giving her throat a couple more gag-inducing prods while he finished hardening, “now to see how well you-” He slammed his hips forwards without warning. “-take it!” Hermione’s eyes filled back as his cock bulldozed it’s way down her gullet, forcibly spreading the walls of her throat around him without a care for the nasty, spluttering, **** sound that spilled out of her mouth along with a torrent of spit. “HHLLLLRRRRRRRRRKKKHHHH!” He dragged his cock almost the whole way back out of her throat before slamming home again. “GLRRRRRKH! HHRRRRKH!” She felt her pussy dripping as he began to pick up speed, her cleavage already shining with spilled drool.

“GLUHK! GLUHK! GLUHK! GLUHK!” His balls - so much bigger than a muggle’s, her brain ‘helpfully’ pointed out - slapped wetly against her chin with every thrust as she began to settle into his rhythm and grasp what Malfoy was after. He clearly didn’t want a slow, sensual sucking from this rented cocksleeve; he wanted a brutal, degrading face-fuck, with plenty of theatrical gagging and ****, waterfalls of frothy suckslop and tear tracks of ruined makeup. “GLUHK! GLUHK! GLUHK-GLUHK-GLUHK-GLUHKGLUHKGLUHKGLUHK!” Well, Hermione couldn’t give him ruined makeup, on account of not wearing any, but she could sure as hell give him the nastiest, noisiest throatjob he’d ever had!

By the time he finally mashed her face against his crotch and let her feel his balls throbbing against her chin as he poured his first load into her, she wasn’t sure if her giddiness was from having her first proper customer or from oxygen deprivation. Then he pulled out, ever-so-kindly giving her the opportunity to gargle the last few ropes of syrup-thick jizz as he shot them into her open mouth, and went to toy with Rose some more while her other clients stepped up.

Two stout men, bordering on fat, with cocks a little shorter but far thicker than Malfoy’s, did get a ‘proper’ suck; Hermione eagerly alternating a cheek-hollowing slurpjob with frantic stroking as she swapped back and forth between them. The next three didn’t want her mouth, instead having her brace herself against the window as they spread her asscheeks, yanked out her buttplug, and thoroughly gaped her needy little pucker one after the other. Her memories began to ooze and bubble as the next one pressed his wand to her temple and did something that left her gasping and panting from the pressure of the front of her thong against her cunt, before ripping them off with a snap of floss-thin strings and knocking her to the compartment floor so he could pile drive his fat shaft into her pussy, a constant screaming orgasm baking her brain so badly she had to be bodily contorted into a doggystyle position by the next man.

She mashed her lips against Rose’s as they were both taken from behind, tongue-kissed each man’s asshole as they took turns filling the raven-haired girl’s cunt, and muffled her orgasmic shrieks in the other woman’s cavernous cleavage as she was buggered by two cocks at once. She soundly lost a contest to see who could get their half of the group - one for each hole, one in each hand and one between each pair of tits - off fastest, but scooped the aftermath off of her body and slurped it down so quickly that she had time to take seconds from Rose’s and beg for a twelve-man bukkake. She was slapped, groped, backhanded, choked, spat on and pissed on, thanking her tormentors as best she could for all of it as they left both girls sprawled on the floor, stuffed to the point of overflowing and so caked in spunk that without magic they’d be smelling of it for weeks no matter how hard they scrubbed themselves.

When she finally came to, head swimming and body aching, she realised two things; that Rose had been kind enough to clean her up - if not empty her holes - and that she’d never cum so hard, never mind so often, in her life. “Fuck,” she groaned, grabbing her wand off of the seat above her head and grinding the tip against her puffy, overstimulated pussy, “that was… Holy shit…” Rose just groaned in agreement, lazily fucking herself with her own wand to the men’s parting gift - a large, moving photograph of Lily Potter being used like a fleshlight by what Hermione could only assume was a Troll.

“N-Not bad for my first group service,” the brunette half-slurred cheerfully.

“Feels like I’m gonna cum just thinking about it,” Rose agreed, “didn’t think Malfoy’d get so brutal with your throat. So fucking hot.”

“And I could feel how hard they were pounding you when I was tonguing their arseholes,” Hermione fired back, a clear note of approval in her voice, “never mind how it still looks so tasty; how is your cunt not inside-out?”

“Welcome to being a witch,” the raven-haired slut grinned, “we’re made for this, and it’s wonderful.”

With Hermione’s surprise ‘Welcome to the Magical World’ party having taken up so much time, there’s just one more thing of interest that occurs before the Express pulls into Hogsmeade Station…

Option 1: It's Harry, completely unable to process Rose's state even as he notices Hermione basking in the afterglow.

Option 2: One of the girls' female yearmates, potentially with one or more men in tow.

Option 3: Something seemingly innocuous; the lunch trolley, prefects doing a meet-and-greet, etc.

Option X: Something Else - or a specific variation on another option.