Now well over eight feet tall, the top of the door only barely met Dust’s chest. She was far too wide to easily fit through it horizontally, forcing her to duck and turn and squeeze her body out slowly. Her cock brushed gently against Rarity's wall, and she just barely suppressed a lewd moan. A maid had to remain professional at all times. No vocalizations of her pleasure unless Mistress Rarity allowed it.

But it all felt so fucking good. Like she was constantly on the very brink of orgasm without quite reaching that final edge. And she was so big! And getting bigger! Already she had to slouch slightly just to avoid bumping her head on Rarity's ceiling. "Of course, Mistress Rarity," she replied calmly, her voice just barely quivering with desire as they made their way to the living room. Time was of the essence here. Soon, Dust would be too big to comfortably maneuver in the hallway. And soon after that she wouldn't be able to move at all. And once things reached that point, well, she didn't want her mistress to have to pay to repair her home and place of business because of her failure as a servant.

"Aah..." Rarity suppressed a moan as the spark of magic ran over her. There it was: 'mistress' - the trigger word. She could feel her stride lengthening, slowly but perceptibly. Bones popped and skin stretched, propelling her just that tiny bit upwards. Her shirt, nearly soaked through with sweat, felt increasingly constrictive as warm Rarity flesh greedily ate up every free inch of space. Even her panties felt tight, the beginnings of a wonderfully sensitive new appendage growing between her legs.

And, just like that, it was over. "Hmph." Rarity grunted, disappointed that her growth spurt had been cut so cruelly short. She knew, of course, that the enchantment on Dust's outfit would channel more and more magic into her with every use of the trigger word, but she wanted it all now. Even that barest drop of a taste of what Dust was undoubtedly feeling every second had made her something of an addict.

"So, Lightning," she began, taking a seat on her widest and sturdiest couch. She indicated a sizable patch of carpet, on which her newly hired maid could rest comfortably... seeing as there wasn't a chair in the world that could hold Lightning Dust's weight now. "Now that we're all comfortable, I'd like to get to know you a little better. We are going to be spending plenty of time together, after all! Why don't I ask you some questions, and you answer with whatever you're comfortable telling me?"

Dust bowed low, her cock nestling gently between her colossal breasts. The mere touch of cockflesh against soft warm breast fat drew a thick gout of precum from the sensitive organ - enough to dwarf any normal stallion's orgasm. It soared over Rarity's head only because the smaller mare was sitting down - had she been standing she would have been just about eye level with the beast of a penis. Dust broke the bow, standing back at her full twelve feet - and her growth showed no signs of slowing down - before obediently kneeling on the ground before her owner. Even with that advantage, Rarity was just barely on eye-level with Lightning Dust's breasts.

"Yes, mistress,” Dust droned, her head fogged with pleasure. “Whatever you ask, I will answer. I live only to serve you. I am your humble servant, your slave, your property. I belong to you, Mistress Rarity, to use as you see fit." She lowered her head respectfully, her cock quivering with increasing intensity as her monologue went on. It took all of her willpower not to cum from submission to her owner alone.

The spell on Dust's outfit processed the trigger words faster than Rarity could herself. She opened her mouth to respond, only to let out a long, throaty moan. "Oooooh yessss," she rumbled, eyes closed in satisfaction. One deep breath went in, her tits rising like dough on her chest, but refusing to fall back to earth as she breathed out. There it was.

Every nerve in her body felt like it was on fire as she billowed outward. The straps of her plain white bra dug into her skin as they struggled to contain her. Her panties had long since given up trying to hold her newly grown dick, a dark, slick stain trailing down her jeans as the lengthening cock snaked down her leg. Rip, rip, rip, fabric tore in a dozen tiny spots across her outfit, cotton and denim alike compromising to contain an ever more massive Rarity. Creamy white flesh spilled out through the tears, her shirt creaking as if to beg of her ‘Please - no more.’

By the time the growth spurt ended, Rarity could finally look down on Dust, her maid now at neck-level... while still on her knees. She shifted idly on the couch, her clothes straining against her every movement. Any sudden moves or flexes - or, Celestia forbid, another use of the trigger word - could leave her completely naked, and that would simply be dreadful.

"You're a very quick learner, Dust," she chuckled. "Flattery will take you quite far in your profession." She stuck out a leg, nudging her foot against the sweltering, squishy warmth of Lightning's overfull balls. “Your future employers will most certainly appreciate it.”

"Wh-" Dust cut herself off before accidentally speaking out of turn. It wouldn't do for the servant to be asking questions of the master, but still she burned with a desire to know what had just happened. Why had Rarity grown? And how could she make her grow more? It was, after all, only appropriate for the mistress to be bigger than the slave. But Rarity stopped growing eventually, and Dust still slowly swelled, bigger and bigger. She groaned as Rarity pressed a soft foot against her swollen, heavy balls, even the slightest stimulation enough to prompt a veritable geyser of precum, sick and translucent, coating more and more of the surrounding room. Her balls churned loudly, a deep, primal, lustful growl for release.

"But why this particular line of work, anyway?” Rarity asked. “Ponyville has plenty of jobs available to ponies who can't find work elsewhere. One simply has to wonder! So tell me: are there any other reasons you decided to become a maid?"

"Gh-aaaaaa~" Dust groaned. Her mistress had asked her a question, and it would be rude not to answer immediately. "I had tried so many other things, Mistress Rarity. All of those jobs for ponies who couldn't find work, I've tried and failed ahaaAAAAAaat" another viscous spurt of precum. "Oooooh, Mistress, please, I can't answer you if you keep doing thaaahaaaafuckkkkk gonna cummmmmmm~"

"Another important skill for a good maid," Rarity said, eyes fluttering as a fresh wave of growth kicked in. She rolled her expanding sole over Dust's churning, sloshing sack, grinning as her toes crept up onto her maid's pre-slicked shaft. "Proper self control. No matter how good it feels, the mistress's pleasure is your first, and most important, concern."

She spread her legs wide, thighs bulging big enough to tear her jeans to tatters. In a single, drawn-out riiiiip her burgeoning erection tore its way up her pant leg, the flared head of a throbbing black obelisk waving just before Lightning's eyes.

"To illustrate the point," Rarity began, sliding her sole over Lightning's fat medial ring, "I'll let you in on a little secret! Referring to your mistress by her proper title makes her grow. Bigger and bigger, and - mm - bigger, perhaps even until you look as small to her as any other pony does to you. So..." Rarity grinned. "My next question: Just how big do you want your mistress to get?"

"Bigerrrrrrr," Dust groaned. Her breaths came fast and shallow, and she gritted her teeth tightly to hold back her overwhelming arousal. "... As big as - ooooh- - as big as Mistress Rarity desires me to make her~"

"Oh, you're too sweet!" Rarity jerked her hips as another surge of growth ran through her - the strongest yet. The tip of her drooling python slid up against Lightning's muzzle, then stuck there as her growth made up the distance on its own. The boundary between plush white Rariflesh and overstretched white fabric blurred more and more, until the shirt exploded off her in a burst of shredded fabric. Rarity shuddered, a need for more and more struggling for dominance over all rational thought. "Still... You say that, Lightning Dust, but I only heard 'mistress' once. I'm not quite sure you meant it! Would you like to prove me wrong?"

Dust's eyes locked onto the quivering obsidian shaft before her, her whole body quaking with the effort it took not to suck it right now. A good maid didn’t do anything without her mistress's say-so. "Yes, Mistress Rarity!” she said, half in response and half to keep her mouth busy. “I live only to serve you, Mistress Rarity! It's only proper that Mistress be bigger than her slutty little slave! That Mistress be bigger than everyone and everything! Mistress must be the biggest! Overwhelming! Mistress needs to grow and grow and her humble little servant is only happy to help her reach that point! Mistress mistress mistress mistress mistressssssss~"

"Oooooh~" If the previous growth spurts had been waves crashing over her, this one was the tsunami. The all-encompassing tidal wave that would dwarf all others. She could feel it building inside her, the first warnings emerging as short, rhythmic bursts of size. "Oh..." Rarity hiccuped as she jumped three inches all at once, the couch whining under her new weight. "Oh my!"

She staggered to her feet, balls the size of Lightning's head - and pulsing bigger with every breath - swaying ponderously between her legs. She took a few staggering steps toward the door, pre-puddles splashing bigger and messier with every jolt of growth. "Come along, Lightni - hic!" Rarity hiccuped again, surging another three inches. She was nearly as big as Lighting Dust now, if not bigger, and still the full force of it had yet to hit. "Let's step outside before we make a mess bigger than you can clean."

Lightning Dust dutifully followed Rarity to the rapidly-becoming-far-too-small-for-either-pony-to-fit-through door. "Yes, Mistress," she replied without even thinking of the potential consequences. Not that she would have objected to Rarity hypothetically outgrowing her home, in theory, but she would have to clean it afterward. And that would be... difficult.

"Oh, this is going to ruin my mane..." Rarity grunted, trying to squeeze her way through the door. The larger-than-normal doorway had seemed a little much when she'd first bought the place, but now she was both too tall and too wide to fit comfortably. Particularly at the chest. Try as she might to squeeze herself through, there simply wasn't enough room to fit all that Rarity past it. At Lightning Dust's latest mention of the trigger word, another jolt ran down her spine. "Hic!" Crack! Another surge of growth forced the doorframe wider, the wood bending and cracking around her massive form.

"Well, there we are!" she said, slipping out into the warm afternoon sunlight. She raised her arms over her head, hands creeping up over the second floor as she grew in ever greater spurts. "My, does it feel good to streeetch after spending so much time in such a cramped space. Don't you think so, Lightning?"

"Yes, Mistress Rarity," Dust replied, bowing low once again, coaxing another few gallons of pre from her dark blue shaft. Standing back up, she found herself just barely coming up to Rarity's armpits. So close, but at least now Mistress was bigger than her servant, as was proper - though Dust still felt herself growing bigger and bigger. She’d have to work extra hard now to keep Mistress ahead of her.

"Mmhm!" Rarity sighed, basking in not only Celestia's warm sun, but the attention from all the surrounding ponies. She'd have thought by now the town would be used to the sight of her nearing two stories tall, but some things they simply couldn't be expected to get used to. She bit her lip, cock twitching as the growth magic roared inside her. Oh, it was so close! It wanted to be free, to make her the biggest, most beautiful mare in all the world. But not yet - oh, not just yet. She had to spread it out. Use it sparingly. Make it last.

"Next lesson, Lightning Dust!" she said, stepping toward her cute little maid. Dust's own growth kept her from shrinking quite as fast in Rarity's eyes as everything else, but next to Rarity she still looked practically like a child. The warm, pillowy weight of Rarity's chest pressed down on Lightning's bust, threatening to swallow her head up in her soft, inviting cleavage. Their cocks pressed together, slip-sliding over each other with every inch their owners grew. Rarity gasped as another surge hit her, slathering Lighting's shaft in a blob of pre.

"Next lesson..." she repeated, her train of thought interrupted by her barely restrained expansion. "Is that you must make yourself comfortable with being seen with your mistress." She sat herself down next to her boutique, back rising slowly against the walls. "Why don't you show everyone how comfortable you are?"

"Yes, Mistress Rarity." Dust bowed again, and then knelt down before Rarity. "I will do whatever you ask of me." She leaned forward, the tip of her muzzle just barely making contact with a monolith of black flesh that put her own member to shame. "Mistress Rarity," she breathed quietly before inhaling the powerful musk of her owner. She gently nuzzled the enormous cock. "Whatever you say, mistress~"

Rarity jumped another foot right there. Her cock pulsed, a blob of pre trickling down over her loyal pet's head, its travel delayed ever so slightly by her lengthening shaft. "Mm, you're a very good listener, Lightning," she said, "but the very best maids know how to take some initiative. Don't just tell me how comfortable you are. You have to make sure everyone watching knows it."

"Yesssssss, mistress," Dust hissed. She cooed as Rarity grew again, the black pillar of cockflesh swelling bigger and thicker and harder in Dust's grasp. She squeezed it, and pressed her whole body against it, pushing herself up and down all over it. Their massive lengths - Rarity's being significantly more massive than Dust's - slid against each other, aided by the gallons of gallons of slick precum that the smaller mare's cock was still spewing. She squeezed her enormous breasts tight and firm, and licked greedily at the shaft. "Oooooh, please, let me cum~ Please put your huge cock in your servant's unworthy pussy, Mistress Rarity~"

Rarity could feel the growth welling up inside her, the primal magic waiting to be freed. Soon, oh so soon. Cracks spiderwebbed in the wall at her back as her head inched up the boutique. Dust's precum and hers mixed together into a growing sticky pond - nigh on a sticky lake - forcing everypony watching to back further and further away.

"You've been doing so well," she said, grinning. "I suppose you do deserve a treat." In a single, smooth motion she put her hands around Lightning's waist, flexed her trunk-like arms, and hoisted the smaller pony up over her monolithic meat rod. She could feel the heat of Dust's arousal, only a foot away from the sweltering sauna boiling around her own cock... and shrinking as her pet continued to grow in her hands. That gave her an idea. "One final trick, though," she said, still holding the squirming pegasus level. "Tell me how much you want it. Tell me what you would do to get it. Tell Mistress Rarity exactly how much you need her fat black marecock."

"Gnnnnnn~" Dust groaned pitifully, surging a few feet from sheer arousal - though she still wasn’t even close to matching her mistress. "I need it more than air, more than food, more than anything! I’ll do anything you ask. Anything you desire, my mistress. My goddess." She squirmed as Rarity grew again, pulsing bigger and bigger around her and above her. "Biggerrrrrrr," she moaned, gears slowly turning in her lust-addled mind. "Mistress Rarity must be bigger. Mistress Rarity must be biggest. Mistress Rarity must be the goddess that she deserves to be, and only I can make that happen, Mistress Rarity." She squirmed, her cock spewing thick precum like a firehose. "Mistress! Mistress, mistress, mistress, mistress, mistress, mistress, mistress, mistress, mistress, mistress, mistress, mistress, mistress, MISTRESS!" She screamed at the top of her lungs, over and over and over and over, showing no signs of stopping any time soon.

Whatever Rarity had been expecting from her little pet, it certainly hadn't been that. It was, however, a very much welcome surprise. Her eyes rolled back into her head, a deep, guttural moan building in her throat as the magic crashed over her. An increasingly tiny Lightning Dust slipped from her fingers, bouncing off the slick flared head of her cock and landing snugly between the shaft and all the rest of Rarity.

"Mmm, oh! Keep that up!" All that Lightning Dust, in her barely-fitting, cum-soaked maid costume, made for quite a sensation. And all the while she was still chanting, yard upon yard of supple white unicorn booming outward with every "Mistress!" The boutique crumbled behind her, bulldozed by Rarity's expanding rear as legs closed like walls around town square. Her ever-plumping balls churned and sloshed with an ocean's worth of seed, precum streaming down her shaft like a waterfall. "Almost there! Keep it up!"

Dust paused her wild chanting only to squeal with orgasmic joy at her Mistress's continuing growth spurt. She threw herself forward, tightly hugging at whatever parts of Rarity's now tree trunk-sized cock she could get at, enveloping and humping one boulder-sized, musky testicle. She screamed - "Mistress!" - over and over with wild, orgasmic abandon. "Cum, mistress! Cum all over me, mistress! Drown the world in your sweet, divine cum, Mistress! Mistress mistress mistress mistressssss~!"

With a final earth-shattering jerk of her hips, Rarity came. A volcanic eruption of hot white cream shot into the air, more and more every second as her growing body consumed all available space... and made some more, dirt and structures alike pushed out of the way to make plenty of space for Equestria's new goddess. Rope upon rope of cum splattered back to earth, swallowing ponies whole and lathering houses a mile around in a thick layer of sticky unicorn spunk.

Eventually Rarity's orgasm tapered off, her screams of pleasure fading into satisfied sighs, but that was by no means the end of anything. Even now, she could feel the magic coursing through her, her balls already bloating even larger with fresh seed, her cock stirring to life as another spurt of growth coursed through her body. The geography town itself was increasingly molded around her prone form. "Well!" she said, a smile on her lips. "That was very good, Lightning Dust. I've no doubt you have what it takes to be one of the best maids in the business."

"Gnhaaaaa~" Dust moaned lewdly, rapidly building up to her own cataclysmic orgasm - though in her case, the term was much more figurative than it was for Rarity. Building and building and BUILDING, but never quite reaching that moment of sweet release. That wouldn't come until certain conditions were met.

"Ooooooh, mistress, please~ Please let me cum~"

"Of course, pet," Rarity giggled, reaching a finger nearly as tall as Lightning herself down to stroke her little pet's needy cock. "You've earned it. Mistress permits you to cum."

"YeeeeehEEEESSSSSS!!!!" Dust screamed, louder and louder and louder, a lewd crescendo that built and built and built as Dust grew. Bigger and bigger and bigger she surged in wild, uneven spurts in rhythm with her cries of bliss. "More!" Her cock convulsed under Rarity's ministrations. "MORE!" She quivered as she felt a handful of the few remaining buildings in Ponyville get crushed beneath her increasingly massive form. Bigger and bigger and "BIGERRRRRR!" until finally, in a rapturous explosion of pure bliss, and one final cry of "Mistress!" Lightning Dust came. Hard.

The resulting geyser of cum was dwarfed only by Rarity's earlier eruption, but the sheer volume of seed unleashed was still staggering by virtue of her sheer size - only slightly smaller than her goddess. Everything in a mile was coated in a thick layer of Rarity's fluids, and everything in a half-mile was further coated in a layer of Dust's. Gout after gout of thick white fluid shot up into the sky, raining down on the town below - and beaning a passing cyan pegasus directly in the face.

"Argh!" Rainbow yelled as Lightning's cum swatted her out of the sky, pinning her down in a lake of Rarity's own juices. What emerged looked more like a pale blob of sticky pony batter than Rainbow Dash. She wiped as much of it off her as she could, wings whirring as they struggled to shake off the gluelike cum. "Ack!" She spat, looking up to the colossal naked unicorn lying before her. "I knew you were behind this, Rarity! What did I tell you about brainwashing my friends and flooding the town in cum?"

"Moi?" Rarity looked almost scandalized, one hand covering her face in mock horror... the other gently stroking her stiffening cock. "What makes you think this was all my idea?"

"Um..." Rainbow gestured to the giant pegasus snuggled up at Rarity's side. "Because Lightning Dust's in one of your maid outfits, acting like your personal sex slave?"

"Well, yeah. That was the point." Dust rolled her eyes. "'s what she paid for, at least." Dust got up and stretched, glancing around to survey the damage. "Dang, we made a huge fuckin' mess. I'd say this counts as you getting your money's worth, right? I mean, if you go for the whole 'I wasn't satisfied' refund thing I don't get paid and fuck that."

"No, no!" Rarity chuckled. "I'm very satisfied. You can be assured I'll recommend you to all my friends."

"Wait..." Rainbow Dash's eyes widened as she put two and two together. "You hired her for this?"

"Well, of course, darling." Rarity said, as if it were the most obvious thing in the world. "What else can I do but roleplay now? I did promise no more brainwashing, and a lady never goes back on her word."

"Awesome.” Dust nodded. “Cleanup crew'll be by later today. We've already got your full payment so don't worry about logistics or anything, we've got everything covered. Ponyville'll be back to normal before dinnertime." Dust held a hand out to the larger mare, pointedly ignoring Rainbow Dash beyond a brief dirty glare. "Thank you very much for choosing Rooms and Brooms Erotic Roleplay and Cleaning Services. The only thing we’re better at than cleaning messes is making them. And on a personal note, it was a real pleasure doing business with you, Ma'am. Of course," she licked her lips, cleaning off a fraction of a fraction of the thick coating of cum that covered her entire body - from both involved parties, "you don't need me to tell you that."

"Cleanup crew?" Comprehension dawned slowly and terribly on Dash's face. "You mean the town’s volunteer pegasus cleaning squad? This was the special assignment I was going to be doing today?"

"Was it?" Rarity sighed, hands speeding up as pre drooled in streams down her shaft. "Goodness, what a task! I do hope they're paying you well for it."

"They'd better," Rainbow grumbled. Shaking off the last of Rarity's cum, she flew off into the distance, muttering about needing a storm cloud and scents she'd never be able to wash out. Dust watched Dash fly off with no small amount of smug satisfaction. Perhaps this job wasn’t so bad after all.

And, as Rarity watched the rainbow streak disappear into the sky, it occurred to her that she still needed to hire a maid. Her boutique, or what was left of it after being flattened under her expanding body, was still in dire need of clean-up! A grin settled over her face, her strokes picking up in tempo as the perfect candidate came to mind. Why, yes, she did know a certain feisty pegasus who'd look just adorable in a maid outfit...

Author's Note

The second part arrives! Thanks again to uni for being an awesome rp partner and in general a great person to work with, and I'll see all y'all for the next installment in Rarity-femdoms-minor-villains.