Knock-knock-knock.

Rarity waited patiently, hands folded calmly behind her back. Around her, the innocent songs, chirps, and squeaks of Fluttershy's whitemeadow menagerie filled the summer air, but her thoughts lingered in a thoroughly less clean area.

The doorknob clicked. In a heartbeat, Rarity was once more standing tall, eyes bright, cheeks rosy. She rolled her shoulders backward, happy to let just a few inches of cleavage poke out over her neckline. Why, one simply had to compensate where she could, and it never hurt to hold one's self with confidence! And if she was simply admiring her now-petite bust before its hopeful expansion into sheer decadence, why, that was just her prerogative, wasn't it?

The door swung open. Rarity's smile stretched wider, ready to greet Fluttershy with a cheery how-do-you-do.

But the pony on the other side of the door was quite the opposite of her effeminate friend.

It was...a wall. Bricks and everything. A row of thick, sharp-angled domes filled the space immediately in front of her vision before climbing up another full foot above her head. A mass of red, thick and hard, filled up the entirety of the doorframe. The carefully hewn work of some master builder, no doubt

Rarity's gaze tracked up - and up, past a jutting-out shelf of red - and up, and up - until she met Big Macintosh's kindly green eyes looking down from far above the top of the frame inside.

"B-Big Macintosh!" she stammered while she pinched her fingers together to restrain herself from grabbing. She frantically tried to fix the smile back onto her face - which wasn't exactly hard, given how...impressive the sight was before her. It was more the deep blush on her cheeks that made up the problem, crossed with the rather...distracting bulge at his crotch. His bare chest and muscles made her blood flush hot enough, but goodness, it looked like Fluttershy wasn't the only one who'd been doing some growing now was it? And in so many different places...

She realized abruptly that she was ogling. Again. Her voice cracked, but she managed, "It's...been a while, hasn't it?"

He inclined his - massive head; dear Celestia, but he had to be nearing nine feet tall! - once. "Eeyup."

Rarity's smile broadened. At least one of them wasn't falling apart. "Would Fluttershy be home, by any chance?" Her lushly proportioned thighs crossed, glutes tensing. Oh, but that rich, rumbling, earthy voice -

"Eeyup," he said, and stepped aside. Wetness slid betwixt her legs, warning her to step carefully.

Perhaps in more ways than one.

In but a moment, a cheery, hurrying Fluttershy was at the door, her own curves more then ready to bend the frame outward - but Rarity's gaze was still seized lock-tight by Macintosh's physique. The sight of that positively titanic bulge bouncing over his thighs - why, it had to be larger than her head; even at his great size, it was proportionately enormous! Soft now, she could hardly even glance to the side without thinking, 'hardness.' His jeans looked painted-on, every striated, corded muscle showing through as his bulk strained them to the breaking point -

" - was actually so very happy that you wanted to join us," Fluttershy was saying. The sunshine of her voice and smile cut through the rather heated haze of the moment. Rarity shook herself back to reality - and quickly averted her gaze from Big Mac's well-padded groin. "He's always thought you were such a sweetheart, and would love to see you try your hand at fashion in my size."

"Oh, my." Despite herself, Rarity found her cheeks blushing as red as Mac's hide at that. "Truly?" she asked, covering her full lips with her fingertips in embarrassment.

The behemoth himself only nodded contentedly. "Eeyup." He needed little else, as the rumble threatened to shake her clamped thighs lose simply from the joyous depth of it all! As Fluttershy snuggled into his side, the top of her head only tall enough to reach the top of his steel-sculpted abs, he gave a rumbling chuckle. "Ah know 'Shy's been strugglin' mighty hard to feel pretty, so havin' a good friend with her could help out."

Fluttershy squeaked in evident agreement, though her face reddened in clear embarrassment. Big Mac only smiled, and reached down to give her massive rump a lovingly possessive squeeze. She all but melted in his torso-thick arms, assflesh overflowing his giant's hands as her knee-draped tits wobbled and shook.

Rarity, meanwhile, was still recovering from the slicks of hot liquid sliding down the inside of her legs. Sweet Celestia, but the sound of that voice - and that musk alone -

Why, it'd been enough to make her cum. And she was still standing outside!

"Oh!" Fluttershy chirped, pulling away from Big Mac. He grunted in clear displeasure as her curvaceous body withdrew from his chiseled one - though a small, vacant smile did flicker across his face as the curve of her bountiful cleavage clipped across the bulge in his jeans. "How rude of us! Please - come in! Would you like any tea?"

"Oh, yes," Rarity said. She stepped inside after them - though had to stifle a moan of awe (and, if she were honest, lust) when she felt the floor of the small cottage shake when Big Macintosh's foot hit the ground. "Tea would be lovely."

Fluttershy clapped her hands together. "Oh, wonderful! Mac, would you get the tub from out back?"

The titan just nodded his head, echoing "Eeyup." Rarity watched him go - and had to keep down an indelicate squeal of incredulous arousal as she watched his mighty rear fight against the confines of his tight-packed jeans. And those broad shoulders! Had he not stood hunched over, they would have risen between the slats of the roof; as it was, Big Mac's ears scraped against the very wooden beams holding it up.

He'd always earned his name in her wistful mind. But Rarity remembered him as a six-and-a-half-foot giant of a stallion, not this wonderful, gorgeous, beautiful hulk of an Adonis! She shivered - and felt her pussy lips moisten anew when she pondered the idea of her tits being large enough to comfortably sandwich such a monstrous manhood between them.

And then she fully processed Fluttershy's words.

"What tub?" Rarity said aloud.

It was a few moments before Fluttershy returned, now carrying too steaming mugs of tea. Rarity accepted hers gratefully, taking a dainty sip as Fluttershy set hers down. From the back yard came a heavy thwunk, and a grunt of effort.

Fluttershy, meanwhile, had retrieved from a drawer a pile of...plastic coverings? Rarity watched, bemused, as Fluttershy ruffled the folded-up plastic in her arms. Then Fluttershy met her eyes, smiling shyly.

“Would you help me cover the furniture?” Fluttershy said. She nodded toward the couch and chairs dotting her sitting room. They’d already been pushed toward the walls, leaving a large empty space in the center of the room. “It’s easier with two ponies.”

“Of course!” Rarity wasted no time in grasping the top of one of the plastic sheets, though she couldn’t help but eye it oddly as Fluttershy picked up her end. It was some effort, Rarity noticed with approval, for Fluttershy to hold her grip above the radius of her enormous breasts, but she managed. “Though, if I might ask, what are these for?”

Fluttershy’s cheeks blushed cutely. “Ah,” she squeaked, “things can get a bit messy during our baths.”

“Ooh,” Rarity said. She nodded, instant understanding flooding her. The secret of Fluttershy’s size was a beauty product all along! Some manner of lotion or body wash, perhaps. From one of her animals? Perhaps found wandering in the Everfree Forest?

She briefly entertained the notion of Poison Joke, and dismissed it with a silent chuckle. No, she’d already looked into the idea of using that for any sort of product. Still, she felt a burning curiosity that was only magnified by the clunking sounds coming from outside.

Not to mention a burning sensation coming from...ah, elsewhere. Rarity’s fingers dug between the folds of her dress at her crotch, fingers idly rubbing her suddenly puffy lips. Hopefully, Fluttershy wouldn’t notice over the extreme breadth of her bust.

“But why an additional tub?” Rarity said. They finished settling a plastic sheet over the couch, a soothing crinkling noise echoing as the ends drifted down toward the wood floor. “You have a bath in your bathroom, do you not?”

Fluttershy averted her eyes. “Well - yes,” she admitted. “But, er, Mac doesn’t…”

“Hrm?”

“He doesn’t fit,” she squeaked.

Rarity eyed the door to the cottage’s bathroom. Then she recalled the size of the titan who’d opened the door for her.

Oh, yes, she thought, shivering deliciously. There would absolutely be a problem fitting such a hunk into a confined space. Then she frowned.

“Why does he need to be there?” she said. “Isn’t your product bottled, or tapped, or - “

Fluttershy was shaking her head. The blush on her cheeks was enough to make Rarity bite her lip with a cuteness-driven lust. “N-no,” she said. “He’s, um, very important.”

Rarity mentally shrugged. Then a heavy stomp alerted her to Big Mac’s return - and shook the entire cabin as well.

It was a moment before she realized that the back door had been enlarged - of course it had been enlarged; how else could a bathtub fit through Fluttershy’s original dainty door? - if only because Big Macintosh was simply so enormous that he made even the new oversized double-door look small. He had to duck inside to avoid hitting his head hitting the frame - and in one arm, curled up to his side, he carried a massive steel bathtub.

Rarity’s jaw dropped, eyes wide, as he easily dropped the enormous thing onto the floor. The entire cottage shook, the floor groaning under its weight. W-why, it must have weighed more than a tonne! And the size of it - a quick calculation estimated that surely no fewer than ten full-grown ponies could have fit inside! Why, it was less a bathtub than a pool!

While she was occupied with ogling the gigantic tub, Mac crossed the room - in only two long strides - and swept up his marefriend in his arms. She was tiny - barely larger than just one of his arms, his monstrous biceps flexing carefully beneath her form as they kissed, his enormous muzzle nearly swallowing up her dainty lips. Rarity couldn’t help but whimper under her breath at the sight, especially as one of Mac’s sausage-thick fingers caressed the curve of Fluttershy’s pony-sized mammaries, the overstretched green sweater holding them doing absolutely nothing to conceal their appeal as the overendowed filly squirmed and moaned in her studly god’s arms…

Rarity abruptly realized that she had shoved three fingers past the hem of her dress and was currently fingering herself like a filly in her first heat. She flushed - what was she, some two-bit horny whore? - and instantly drew her hand back. Her fingers were dripping with arousal.

Still… She couldn’t help watch in awe and envy for a few moments more, as Big Mac and Fluttershy finished their kiss, the massive - yet gentle - stallion fiercely meeting his lover’s lips as she caressed his bare chest, soft hands stroking steely pectorals as round and hefty as beach balls. And the way he held her incredible bust - along with her entire body! - in just one arm, curled in the nook of his bicep…

Rarity realized that she was masturbating again. Cheeks darkening, she tore her fingers back - and gasped at the sudden chill to her pussy. Goodness, but what was wrong with her?

Finally, Mac let Fluttershy down, the gentle giant’s massive arm unfolding just enough to let her - and her titanic breasts - drop to the floor. Fluttershy got to her feet with a breathy gasp, cheeks flushed and rosy, eyes as bright as a filly in the throes of her first afterglow.

“O-oh,” she said, still moaning slightly. One of Mac’s massive hands curled around her pillowy ass, and she squeaked, toes curling against the carpet. “S-sorry to keep you waiting, Rarity.”

“No need to apologize,” Rarity mumbled, idly wiping her dripping hand off on her dress. When she saw the way Mac eyed his marefriend again...she shivered. The look in those eyes was so intense - so heated - so strong. She tore her gaze back to the oversized bathtub in the center of the room. “Shall I - oh, I don’t know, fetch a pail of water? I imagine it might take some effort to fill this up.”

There came a low, rumbling sound, like the earth shaking. It was Big Mac - chuckling, his great chest bouncing and flexing as he laughed heartily. Beside him, Fluttershy smiled.

“Oh, no,” she said. “We won’t need water. But - oh, you will need to get into the tub.”

Rarity reached for her top - and then frowned. “With…” She nodded toward Big Mac, the overstudded stallion now eyeing her curiously.

“Oh, yes,” Fluttershy said, nodding. “We’ll just need you to strip down first.”