"Oh, good. You're awake. Finally. That wasn't exactly the best time to be taking a nap, you little lazy-bones, right when I need you most to help me pump up those gains! Well, good thing I'm a super-cool sister, and forgive you for being so inconsiderate," Mia said, towering above me and per usual not bothering to hide her grin, despite the seriousness of this scolding. Finishing a set of bicep curls using fully-loaded barbells, my sibling slammed the metal plates back to earth and inhaled deeply, while fresh sweat rivulets already painted her glamorously-tan workout-sopping figure, as though she hadn't changed ensembles at all. "This is good timing, though. I've been thinking of a great new way to train for squeezing every last drop out of every single lift, and you're the perfect person to help coach me."
Though I didn't expect to be promoted to coach, after serving as the literal inanimate marker for her undulating ass cheeks earlier, I didn't for a moment let myself believe this "new" job would end any differently than the others. Obediently nodding, I let myself be led away by the gym's lone remaining member, given the way her rippling heat waves of anal-fouled pork-and-pepper aroma had effectively claimed the whole building as hers forever. We made our away from the free weights over to the yoga mats. Here, Mia dropped to her haunches as well and spread her sculpted bronze legs out in a near-splits position, though since I was still bowed by weakness from olfactory onslaughts and general submission to her dominance, she continued to loom over me, even seated in preparation to stretch.
"Yep, a good workout can't just be ALL about lifting the heaviest weights, even if none of the other losers in this gym could even touch a fraction of what I can handle in my sleep," Mia announced. "So I'm going to do a little... well, I guess "hot" yoga is the right word, huh? And it's definitely going to get even hotter in here. Only with my own spin on it. And you're going to help make sure I do everything exactly right, shortstuff."
Again I bobbed my head and waited, breathless, as Mia assumed the first pose that made her ass flaunt more egregiously, the bountiful curves of those moony cheeks straining the fibers of her shorts. While it was relieving to be away from my sister's multi-hundred-ton dumbbells which could so easily paralyze me if she dropped one too flippantly, I doubted I was any safer, even on a blank foam floor with relatively open air, while she performed this zen-like exercise. High ceilings or not, there simply wasn't enough space to contain the pent-up gaseous runoff currently stocked in Mia's intestines, and of course the most dangerous weapon of all wasn't the iron bars which could've snapped my neck, but my sibling herself, and the nuclear fallout of sweat-stained meat-simmered farts just itching to be puffed my way.
"Just a little further..." my titanic sibling breathed, reaching herself yet further forward on the mat, while her legs remained outspread, thus continually stretching the span of fabric pressed across her ever-widening crack. I sat behind Mia in abject fear, my gaze dedicated to that flimsy layer of elastic cloth all-too-thin to protect me from an eruption. "...and then we'll get to the REAL exercise. Watch this, Hal. Maybe you'll learn something. At the very end of the stretch, I make sure every muscle is fully engaged, and then I just... relax!"
True to her word, Mia's burly figure firmed when she clenched every bit of her athletic anatomy, showing off sculpting that would've looked more at-home on a monument to a Greek goddess. Then just as quickly, the nine-foot conqueror relinquished all control, which evidently including unleashing the hold on her sphincter, first in lockdown mode and then loosened like the mouth of a full balloon about to blast off. A deep grumble gave way to a high-pitched squeak, and then a fuller, wetter implosion of fog-state defecation. For an instant, an air bubble inflated the back of her buttock-tight shorts, briefly containing the rapidly-expanding new odor-cloud, and then it all came gushing out in a balmy wind through the breathable fibers. She sighed with the contentment of a practiced yogi, and pitched even further forward, so that abominable ass was propped yet higher, ensuring the trajectory of its flatulent payload would spray right into me on its path to refill the whole gym. As I'd come to recognize well, the searing lines of heat fanned out from Mia's conveniently-spread cheeks like sizzling mirages on highway blacktop, instantly creating a fresh film of stinky sweat on my face, and redoubled by the actual flavor of the rectally-belched bomb which accompanied that sweltering rush.
Even though I was already crouching close to the ground, the violence of my sister's new yoga "technique" was enough to knock me straight back again. I heard her chuckle at my dramatic but entirely-earned reaction, as her laughter came in stuttered bursts much like the horn-blats of her gas spiking the squalid air around us and raising the temperature to the level of an oven. Again I squirmed on the floor with Mia's ass again hovering so close by, only with those buoyant cheeks flared as far apart as she could manage, and she showed no signs of ending this stretch yet. If the seam of her shorts split at any moment, and that was certainly a possibility either due to the tenacity of her musculature or simply deterioration of the cloth after so many slimy sewage wafts, I had no doubt that I would see directly into the valley of her crack, with that puckered orifice closing just briefly enough to prep for shooting the next spiraling bout of asshole smog of directly into my mouth.
"Hope you're keeping a close eye on me back there, coach!" Mia cheered. "Because if you're not, then we'll just have to do it all over again, until you can learn to be a real team player!"
She grunted, then, seemingly exerting herself to push out an even louder and more profound rip of anal chemistry. The extra effort forced me to smell the digested-and-processed remnants of not only her bean-heavy breakfast and carnivorous dinner, but other feasts from throughout her week: undercooked steak, foreign spices, broccoli, and fatty animal liver, all having been simmered to an infinitely-worse bouquet in my sibling's guts over time, rotting and roiling together amongst her enzymes. Every newborn pump of her smell was first punctuated by another baritone groan from Mia, when she again clenched her whole beefy physique, then the wobble of her drum-tight ass cheeks flexing and spreading to let out the next specially-prepared storm of shitty, skin-stinging, throat-closing scents.