Discord puffed into existence above Rarity's clearing, stroking his beard as he contemplated his plan to entice her. Dresses and mirros, perhaps? He snapped his fingers to make said items appear, then sat back in the air as he thought. Dresses weren't quite right but... a lightbulb appeared over his head as he grinned and snapped his fingers again. Overly frilly and puffy costumes puffed up on various racks in the clearing, with a box of matching props. He snickered and pulled a camera out, sure to get some good shots of the prissy pony.
Rarity entered the clearing soon enough, looking around the assembled lines or fabric with a gasp and wide eyes. "Oh my, what is this? I mean, it's a little kitschy, maybe, but on the other hoof..." She bit her lip, pacing left and right for a moment before stepping closer to the racks. "Should I? I could never turn designs like these into reality back home, imagine if ponies found them! Not to mention the material costs..." She looked around for anypony to see her before stepping up to the closest rack with a blush, shifting the outfits on it around. "Surely I can take a few moments to indulge. It's not like we are on a time limit, strictly speaking. Just a minute or two, to have a quick look."
The racks were adorned with several costumes, some elegant costume ball gowns with suspiciously puffy rears, others looked like mascot outfits, resembling oversized plushies, and still others were surprisingly squeaky in appearance. Discord flicked his tail, one of the outfits drawing Rarity's attention. It was bright purple and green, silky and smooth, and just a little pudgy.
Rarity's ear flicked as she shifted past the costume, quickly moving the last few selections back until she found it again. She couldn't quite keep down a giggle at the familiar color scheme. "Is that... Spike? Oh, I almost want to take this with me for the next time Twilight ever loses a bet." She poked a hoof into the fluff at the front with another chuckle. "Goodness, it even has his proportions, doesn't it? This Discord character may be horribly tacky, but at least he has an eye for detail."
Discord suddenly puffed up behind Rarity, camera in paw. "Is that a compliment I hear? Goodness, to think the great Rarity finds me eye for detail worth commenting on! I do hope you've found something to your liking in my collection." She said, leaning down a little closer. "You have all the time in the world to continue wandering this maze after all, why not take a break?"
Rarity most certainly didn't squeak in surprise and whirl around while jumping back, and she definitely did not trip into the rack and land in a heap between all the costumes. Anypony saying differently was indulging in baseless rumors and any pictures taken by the Lord of Chaos obviously couldn't be trusted.
She glared up at Discord from where she was absolutely not trying to push a small mound of costumes off of herself. "Do you mind? Listening in on private conversations and sneaking up on poor, unsuspecting ponies... Being evil is still no excuse for being rude."
Discord only chuckled, snapping a few more photos. "Rude? You're the one who decided to wander in and try my outfits on. The least you could do is indulge me a little." He reached down and pulled up a dress covered in brightly colored sequins. Each one glittered in the light, shimmering and shining as he shook out a few wrinkles it had received after falling into the pile Rarity was in.
Discord slipped on the shiny dress, turning about so his back was facing Rarity. "This doesn't make my butt look big, does it?" As he asked he swayed his rump left and right, which swelled ever so slightly with each swish.
Rarity blushed and tried to look away, but found herself transfixed by the sparkling, glittering dress swishing back and forth in front of her. It took her a moment just for her instincts to kick in. "N-no, of course not. Don't be silly, darling, it looks absolutely gorgeous on you." She blinked and blushed a bit more as she realized that she'd slipped into her salesmare mode out of habit.
"Oh, that's a shame." Discord said, looking over his shoulder at his swollen rump. "Perhaps a closer look might help?" She stepped backwards, making sure the glittering dress filled Rarity's vision. "Now, if this did make my butt look big, just imagine how well it'd sell! After all, everypony loves a big rump, don't they?"
"Everypony loves a big rump..." Rarity blushed and stared at the approaching sequin-covered butt, trying to back away but getting her hooves tangled in the costumes she'd spilled earlier, tripping and plopping her butt into a small pile of plush and fabric. "I-I mean, I suppose some ponies do try to accentuate their posteriors but they, uhm, don't usually tell others that."
"Well, they shouldn't have to tell anypony, it should be obvious! A big rump is a best rump, bringing all the attention towards you, making everypony look your way at that puffy posterior~" Discord bounced backwards, smothering Rarity under his rump for a moment before he bounced back again, landing behind her. "Oh, goodness, but your rump is hardly puffy enough!"
"It... isn't?" Rarity blushed and lay dazed between the costumes for a moment, only slowly sitting up and looking around. "I... I shouldn't listen to you. To someone who just... just bounces on ponies..." She scrambled back to her hooves clumsily, swaying in place. "J-just out of curiosity though, how would one go about, uhm... making their rump puffier? Some sort of outfit to make it seem bigger, I assume?"
Discord nodded, picking up one of the outfits to hold it over himself. "That's a lovely idea~ An outfit to accentuate your rump! But that can't be all, something thick and fluffy around that rump will surely show it off too. Something puffy, cushy, and crinkly..." He folded up the colorful sleeper, squishing it into itself several times over until he was holding a puffy diaper in his paws.
Rarity shook her head and blinked a few times to make sure she was seeing right, then blushed and swayed a bit in place. "O-oh my, is that...? I mean, s-surely there must be other ways to get a puffy... cushy..." She swallowed and blushed more. "C-crinkly rump?" She stepped forward a little, staring at the colorful diaper. "W-well, it is rather pretty..."
Discord placed the diaper in front of Rarity, starting to dig through some of the costumes again. "It's only the start, of course. You'll need a costume on top of it to really sell that swollen tush. Something elegant, gorgeous, and properly plush." He lifted up a dragon suit, one that seemed not too dissimilar to the Spike outfit she had been admiring before, though with a color scheme matching her own.
"O-oh, yes, of course..." Rarity giggled and blinked again, watching the costume with glazed over, faintly swirly eyes. "I knew there was something off... A good s-swollen, uhm, tush needs something elegant and gorgeous and properly plush." She blinked and frowned a bit, pondering if that sounded right, but the outfit Discord held was definitely elegant and gorgeous like her and nopony could deny that it was very plush, so it had to be right.
Discord snapped his fingers, and Rarity was suddenly blocked from view by a circular curtain. He tossed the diaper and the suit up over the top and there was the sound of rustling fabric and crinkling before the curtain vanished again to reveal Rarity in her new outfit. Her hind legs spread wide by the bulk of her padding, accentuated by the puff already present in the suit. Discord snapped a few photos giggling to himself. "Why, you look absolutely ravishing!"
Rarity wobbled and swayed in place with her hind legs spread wide, eyes full of swirling colors from when she was surrounded by the glowing swirly and psychedelically colorful curtain. The swirls shrunk to pinpricks for a few seconds every time Discord flashed the camera before they filled her eyes again, her head going from full of colors and fabric and crinkly frills to completely blank and back again, over and over. "A-absolutely ravishing..."
Discord pulled one of the photos out and flapped it about as it developed. "These look marvelous, darling! You really show off that suit of yours well." He said, mimicking Rarity's own accent. "But, you know, the best way to keep that rump of yours is to take all the fluff you can get. You are a dragon after all, and what they want, they take. Especially if that thing belongs in their hoard. And from the look of things, your hoard is awfully puffy." Discord laughed, bouncing his butt into Rarity's.
"M-my hoard?" Rarity looked down at herself, taking in her plushy scales, her thick stubby tail and her big puffy rump, not to mention her large plushy claws. She blinked a few times, the spirals fading from her eyes as she smiled. "Oh yes, my hoard. I really ought to take better care of it." She giggled and shuffled her hind legs a little, pulling a thick diaper from the pile and flipping it up to stuff it into the rump of her costume, all while looking up at Discord with a perfectly innocent smile the whole time.
"You really should. A hoard needs to be well maintained. Loved, cared for, and most importantly, big!" Discord giggled, walking around to get a better look at Rarity's rump, his own still swaying left and right beneath the shiny dress. "Big and round, so nopony can ignore it!"
"W-well, of course... I do love being the center of attention." Rarity giggled and looked back at her rump as well, wagging it left and right before pouting slightly and turning back to the piles and racks of costumes to look for more puffy and poofy things to add to her hoard.
Discord flicked his tail about, puffs of powder filling the air as several more cushy things appeared. Thick diapers, frilly cushy blankets, and overstuffed pillows falling in front of Rarity. "Oh my, how did those get there?" He said as innocently as he could before patting Rarity on the head. "Well, have fun making your hoard grow. I'm sure your friends would love to see it even bigger! Anything puffy and fluffy, they should just hand it over, now shouldn't they? If it makes your hoard grow, it really should be yours." He teased.
"Yesssss~" Rarity's eyes sparkled and swirled, transfixed on the bounty of fluffy, cushy and wonderfully crinkly things. She waddle-pounced forward, grabbing several pillows and diapers at once and stuffing them into her padded rump, wiggling and shaking it a moment to spread the fluffy cushy hoard out~
Discord giggled and snapped a few more photos before vanishing, leaving Rarity to her stuffing and puffing of her cushy, crinkly 'hoard'~