The warm water rippled around Rarity's body, tiny waves crashing against her skin. The heat of the hot tub permeated her hide. She took a deep breath, and shivered with delight as the crisp coolness of the cucumbers over her eyes clashed with the thick, humid steam of the spa. The water lapped eagerly at the round circles of her areolae, her bare breasts only half-submerged by the tub. Her toes curled in delight.

Now this was relaxation.

"Mm," Rarity murmured. "Fluttershy, won't you come in?"

"Oh, of course, Rarity. Just—one moment."

A short grunt—then a sigh of relief. A thin little smile curved Rarity's lips. She'd seen the way Fluttershy's pants had clung to her hips and rear on their way in. Covering up a body like that with sweatpants—as Fluttershy so often did—ought to be illegal. Then again, Rarity thought, her smile twitching, the sheer size of her friend's assets made such efforts nevertheless...fruitless.

There came a delightful little squeak—and then a splash that made Rarity's ears flinch. She picked up one of her cucumber covers and watched gallons of hot, steamy water go slopping over the sides of the tub. Ripples-turned-waves broke against her side, sending her breasts bouncing and floating—but even that was nothing compared to the sight before her. Rarity's eyebrows furrowed, and her muzzle dug into a teasing, knowing grin.

"O-oh, my." Fluttershy's hands flew to her cheeks. "I didn't mean to spill so much water."

"Nonsense, darling." With a pinch of her fingers, Rarity rid herself of the other cucumber slice. With Fluttershy in the tub, there was no excuse not to look.

Rarity flashed her a grin. "There's plenty more."

Fluttershy's cheeks reddened, but she relaxed a little. Her arms and legs, so tense and tight with constant self-control, spread out, muscles going loose as the warm water soaked into her pores and hide. There was quite a lot of her to spread out.

Fluttershy seemed to notice so, too—a good half of the six-foot hot tub was covered yellow, an impressive amount compared to Rarity's own svelte sliver. She chewed on her lip. "I just don't want to leave a mess for Aloe and Lotus to clean up."

My dear, Rarity told herself silently, one look at you like this would leave enough of a mess for anyone to clean up. Her luscious legs rubbed together, thighs pressing against her clit as she eyed Fluttershy's naked form. It was undeniable that Rarity didn't have her own appeal—full, rosy lips; a taut rear; a well-rounded neckline; and a mane cleaned and conditioned to perfection without fail. But next to Fluttershy, she may as well have been plain.

Where Rarity was cool, calculated perfection, Fluttershy was hot, burgeoning sex appeal. Her heart-shaped lips were ripe for kissing, and her mane just made a pony want to run her fingers through it for hours on end. Yet if those had stayed her only attributes, she might have gone through life as an attractive, yet homely mare. It was her other, more physical attributes, that truly drove the senses wild.

Her rump was enormous, a pair of ballooning, spherical glutes to whom any fabric clung like spider's silk. The way she walked was enough to push any hot-blooded adult into libidinous frenzy, with those prime flanks flexing, bobbing, and pushing together. Her hips, always matronly, now flared out into a shelf wide enough to rest one's head on—a circumstance Rarity had found herself fantasizing about more than once. When Fluttershy moved, ponies watched. It was impossible to ignore the swaying, teasing sway of her step, the way every inch of her seemed to ooze an innocent, yet gluttonous kind of lust.

Perhaps it was just the way she was proportioned—even Applejack, bottom-heavy as she was, seemed to walk with a swankering swagger to her step. But Fluttershy was tall, too—and where her rear was large, her chest was massive.

Rarity realized that she was ogling, and abruptly realized that she didn't care. Her friend was simply too...

...delicious.

Those breasts. My goodness, Rarity thought—but those breasts. She herself knew a thing about a weighty endowment, with her own bust pushing an F-cup. But Fluttershy made her look positively prepubescent by comparison.

Each tit was easily large enough for a foal to curl up inside, and still have room to spare. Rarity's thoughts felt woozy at the very thought of it. When she was standing, Fluttershy's breasts fell down nearly to her knees, covering her entire torso past the subtle taper of her hips. Off to the changing panel behind the tub, she could make out the enormous strips of fabric that made up her friend's bra. The strength it must take to heft those things around—Rarity found herself marveling at the sight.

How much must they weigh in all—those glorious, bosom-straining mammaries? One hundred pounds together? One hundred and fifty? Why, they might very nearly outweigh herself! And those nipples—so large, so tender, their tips poking above the surface of the water, tall and round as a thimble and just begging to be fondled and groped and squeezed and suckled—

Rarity's legs crossed into a scissor, concealing her puffy arousal even as her thighs rubbed closer together. And yet Fluttershy carried them around—if not proudly, then still simpling, a pair of great, globular spheres the size of exercise balls bouncing and knocking together upon her chest. Awe turned to lust turned to envy.

"Fluttershy," Rarity began. Fluttershy had just let herself slip fully into the tub, eyes sliding closed—they flinched open again with a sharp little inhale. "Dear, you look even more radiant than our last meeting."

The cute little blush tinging Fluttershy's cheeks was enough to send any heart cooing. "Thank you, Rarity," Fluttershy demurred. "I'm glad you think so."

Even a subtle flex of Fluttershy's thunder-thigh legs—difficult as it was to see them beneath her magnificent bust—was enough to get Rarity's heart pounding. What a rush it would be to have those wrapped around one's head—or, better yet, to own such legs, to stride down the street watching admirers gape in awe at a set of thighs that could suffocate a victim without missing a beat of pleasure.

"Think so?" Rarity said. "Dear, I'm sure that if I took a tape measure to those bountiful curves of yours, I'd find at least a half-inch added since last Tuesday." She let her lips curl into a sultry grin, eyelashes fluttering across the tub. "I must admit that I'm a bit jealous, darling! How do you do it?"

"Oh—I don't know." Fluttershy glanced down at the surface of the water. Her great bosom, over three feet across and wobbling with the gentle ripple of the waves, floated just beneath her chin. "Good genes, I suppose."

Rarity laughed—she couldn't help it. She'd known the shy pegasus for years—and yet it was only over the past several months that she'd begun growing fairer by the day. "Really, Fluttershy," she said. "You can't expect me to believe that. You're up a half-dozen cup sizes from the Summer Sun Celebration, easily."

Then again, for mammaries that large, cup sizes seemed to have lost all meaning. At Fluttershy’s rate of growth, it seemed like only a matter before they’d be dragging along the ground, anyway, rendering the very idea of “bra size” a lost cause. Rarity bit her lip, feeling her core flex with hot, piercing arousal at the image that wrought.

Fluttershy blushed madly at the direct reference to her bust. Still, she shook her said and insisted, softly, "It's nothing, really."

It was a struggle not to roll one's eyes at that. With a thought, Rarity threw caution to the wind. Both hands came to rest, palm-down, on the soft jets of the hot-tub seat—and then she pushed herself off, swimming to Fluttershy's side.

"Come now," Rarity chided gently. Fluttershy gave a muffled squeak when Rarity cuddled in beside her—and moaned under her breath when one of Rarity's hands wrapped around her generous ass and squeezed. Perfectly manicured fingers dug deep into the soft, supple flesh of Fluttershy's rear, massaging her well-padded flanks as Fluttershy's wings bristled and stirred behind them.

"It's not polite to hoard," Rarity went on. She drew a hand up from the water, little diamonds of water-droplets flecking across their skin. Lithe, slender fingers walked across the surface of Fluttershy's bust as Rarity's bosom pressed into her side. Fluttershy's breathing grew faster, and she groaned as Rarity's left leg wrapped around hers. Gods, Rarity thought, staring down at her friend’s enormous breasts. With a little time, they could be bigger than her.

The thought drove her wild with excitement.

"We're friends, are we not? And friends share."

An elegant white finger moved down to fondle at a bright pink nipple. Fluttershy shivered, a clear surge of pleasure rippling through her body. Smiling, Rarity pulled her weight back—if only for a moment.

She waited.

"Okay," Fluttershy finally said. She offered Rarity a timid smile. "I'll show you."