The jar you were in rattled about as Yumi shoulder her backpack and began to walk. As the floor and the wall swapped positions in the shifting bag, you slammed against the glass. A groan came from within the darkness, not your own, but rather one of your fellow victims. Indeed, as your eyes adjusted to the darkness, you could soon enough make out the minuscule figures of fellow shrunken people, a total of three to be exact. The unmistakable outline of rounded ears, suggested they were all were dressed in a near identical Metroville Mice mascot suit. You had no idea how Yumi managed to snatch up so many of the shrunken mascots, but that soon ended up being the least of your worries.
"Um....Faith?" Yumi's voice boomed, its volume contrary to the timid tone it carried. Outside the backpack, the Japanese science team captain had just approached a fairly bottom-heavy gymnast from her own school.
"What's up, Yumi?" The girl, likely Faith, replied. From her tone, Faith sounded like a friendly girl, though she also sounded a bit younger than she actually was.
"It's...uh....I have...." Yumi fumbled a bit, trying to come up with the best way to phrase what she wanted. She finally settled on a matter-of-factual, "The experiment is ready."
There was a beat of silence, during which Faith blushed a bit, shifting awkwardly. A nervous feeling bubbled up in her stomach, one that only caused problems further south. Yumi gave her an uncharacteristically stern look, unwilling to have her months of work spoiled by her assistant getting butterflies.
"I mean...I guess I have been holding it in all day," Faith replied with a sigh, caving to peer pressure.
"Excellent, follow me and I can set up the test," Yumi ended the conversation, turning on the spot and walking off in a different direction.
After an endless clattering of footfalls, you felt the backpack shift. The jars rattled once again as the bag was set down. Overhead the zipper roared like the engine of a truck, bringing in blinding fluorescent light. You caught sight of Yumi's fingers, wrapping around the jar as you were lifted free of her bag. A quick glance around from between the massive digits just across the glass, told you a few things. First of all, you seemed to be in an empty science room with lab tables set out a regular intervals before a massive whiteboard labeled with old Chemistry equations. Secondly, you caught sight of the girl known as Faith. She could easily be mistaken for a child, with a cute round face and a bit of a chubby figure which seemed to focus all the growth of puberty into her rear, something you got a very good look at as Yumi lowered your jar to the ground. As Yumi popped the lid of your jar, you saw that Faith also seemed to be wearing a gymnastics uniform, consisting of a white top with her number printed on the chest and a pair of form fighting purple shorts that barely cleared her backside. The outfit as a whole seemed purposefully designed to accentuate both the flatness of its owner's chest and the curve of her rear.
"Alright...this is the first subject," Yumi explained, quietly, producing a clipboard and pen. She looked at Faith expectantly.
"I-is this really okay?" Faith asked, glancing down at you trapped in the jar and putting a finger to her mouth in thought.
"Faith, I need your help, you're the prime subject" Yumi pleaded, growing a bit more intense and seeming to scare the otherwise kind girl into complying with her science project.
"Al....alright," Faith replied nervously.
At this point you were thoroughly confused as to what was going on, as well as utterly terrified. All you knew was that you were being used for some weird experiment by a Chadwell science nerd, one which apparently required the use of a bottom-heavy Chadwell gymnast. You soon got your answer as Faith stepped forward, standing astride the jar. In a sudden motion, she squatted down, her ass seeming to bulge outward as it grew to the size of a small planetoid, leaving you shivering in its shadow.
"Pants and underwear off, it will interfere," Yumi commanded in a clipped tone, quickly attaching two identical small devices to the rim of the jar.
Blushing a bit, Faith glanced to the closed door of the science lab and then to the second story windows, the blinds for which were drawn. Quickly she hooked her thumbs under the waistband of her shorts and the plain white panties beneath, and with one smooth motion, she tugged downward. The pale mass of flesh composing her twin cheeks was left out on view for you, as well as the dark crack the separated them. Your heart was pounding as you began to recall the name Faith, you swore a friend of a friend had mentioned a girl with that name as well as her awful nickname.
'Farting Faith'
As the light bulb clicked in your head, your fate as well as the jar was sealed. At the command of Yumi, Faith pried apart her cheeks and lowered herself fully onto the opening of the jar. Like a plug in a bathtub drain, her ass formed an air- and water-tight seal around the cool glass rim, with the attached devices preventing any possibility of fresher air flowing down the widened channel of her crack. With her cheeks separated now, you got a clear view of her wrinkled asshole, like some monster's maw, hanging a few dozen feet overhead. Panicking, you ran up to the side of the jar, beginning to bang on the glass to be let out. Outside, Faith was too busy pretending she was sitting on the toilet instead of a jar with a shrunken person to pay attention to your pleas. Meanwhile, Yumi was too cold and logical to worry how horrific it would be to be an inch tall and subjected to a giantess's toxic farts.
PBBBBBPPPPHHHHHTTT
Faith's first fart hammered into the jar. A forceful trumpet of flatulence that ended in deafening airy hiss. It was strong enough to force you into the glass ahead before you staggered backwards, laying on the floor and staring up at Faith's twitching hole. The smell hit you after a second, the overpowering stench of rotten eggs burned at your nostrils.
PFFFFFFFFFFFFFFFFFFFFFTTTTTTTTTTTTTTT
The second fart came just as you were discovering the stench of the first. A long, loud fart that you had the displeasure of watching exit Faith's asshole. The heat was already beginning to rise, causing condensation to fog up the glass. You coughed, trying to stand, eyes watering as the stench grew worse. It felt like your vision was tinted yellow as you crawled back towards the wall.
PBBBBBPPPPHTTT PBBBPPPPT PBBBBBT
Faith clutched at her stomach as her gas became uncontrollable, her bowels pumping out three quick noxious blasts of raw methane. The rotten egg stench was slowly accompanied by the smell of raw sewage. You dropped on your stomach, hacking out a series of coughs. You could barely see anything through the foggy cloud Faith's farts were leaving. Yet if you could, you'd probably be scared of the sight of Yumi squatting next to the jar to jot down her observations. The quiet Japanese girl glanced at the devices, which you now realized resembled digital thermometers.
"I need a higher concentration to determine our baseline," Yumi demanded, prodding the side of Faith's butt with her pen.
"O...okay," Faith replied, a little defeated as she grunted and strained.
The final fart was an absolute bomb, the sound of which you weren't fully aware of due to it exploding from Faith's ass with a literally-deafening blast. Your ears rang as you found yourself thrown against the wall of the jar, head now throbbing. Your lungs burned as the oxygen in the jar was almost fully replaced by Faith's potent farts. A cocktail of stenches invading your nostrils, leaving your mind swirling. The thick fog was impossible to see through, yet it didn't matter since your vision was beginning to darken. The devices on the edge gave off a dimly-heard beep, and changed color. Mercifully, as you fell unconscious, Yumi held up a hand. The jar's concentration had reached what she deemed 'acceptable'. Faith finally stopped her poisonous barrage.
Yumi lifted a fraction so she was at eye-level with Faith's rear. Pinching her nose shut in preparation, she nodded. As Faith lifted her ass off the jar, Yumi quickly replaced the lid -- this one without any air holes, sealing up the gas that had just been piped in courtesy of the gymnast. Turning the jar on its side, Yumi observed your limp form rolling around and sighed. To most it would seemed that you had died in the most humiliating way possible, yet to Yumi it seemed...
1. ...She'd lost a test subject. (Believing Faith's gas to have killed you, she gives you to Faith to 'dispose' of. Faith soon discovers that you haven't actually died and decides to take care of you... whether you like it or not.)
2. ...You were unconscious. (Already knowing this was the likely outcome, Yumi sets the jar aside and continues her testing with Faith. Later on, she might bring you out for a new experiment, or perhaps even for her own personal entertainment.)
3. ...You were faking it. (Suspecting you were only pretending to be unconscious, Yumi decides to punish you by giving you, and the rest of her test subjects, to Nina, the very athletic track and cross-country star of Chadwell and the third member of the science group, to keep for the weekend.)