Soarin had just returned home to his posh, two story cumulus chateau after a long day at the WonderBolt Training Facility. After a day of difficult flight maneuvers and vigorous exercises, it was nice to return to the quiet comfort of home. Better yet, it was the only time he got to engage in his secret pleasures that he dare not otherwise perform. With renewed energy, he made sure that all the windows were closed, the curtains drawn, and that the doors locked, then flew to the kitchen. Soarin went to the fridge and after a moment, pulled out a beautiful apple pie, freshly made from Sweet Apple Acres. Ever since he first discovered their goods at The Grand Galloping Gala, he had become a regular customer, ordering all his confectionary goods from there. Soarin checked the time and after a quick confirmation pulled the coveted dessert out of the oven. Now while the consumption of baked goods wasn't exactly supported by the WonderBolts due to their strict fitness regiment it was by no standard the kind of offense that would require this level of secrecy.
No, Soarin had much bigger plans in mind. He then flew over to the cupboard and flapped up to the highest shelf, where in the farthest, darkest corner, laid a little blue bottle. It was by no stretch of the imagination impressive, just a simple ceramic bottle with glossy blue paint that was slightly chipped in a few place, revealing dull white clay underneath, and a little cork stopper at the mouth, but within this seemingly ordinary bottle laid Soarin's most well kept secret that he and only one other pony knew about. Barely able to contain his excitement, he carefully uncorked the stopper with his teeth and then ever so carefully, allowed three small drops of the content, a liquid almost the exact shade of navy blue as the bottle, fall onto the freshly reheated pie. The drops initially sat on the surface of the crust, but as they began to be absorbed into the pie's flaky, buttery goodness, the entire pie started glowing bright blue, indicating the potion's effect taking hold, before it returned to it's seemingly ordinary appearance.
Soarin held up his creation, tempted to take a bite, but no, he would wait, there were still other things that needed to be done. He quickly hurried upstairs to his bedroom and then straight to his closet. In there, he rummaged through an assortment of various things, including his Wonderbolt outfit, various designer clothing, and boxes of personal keepsakes, finally he found what he was looking for. It looked like many of the other boxes in the closet, if anyone else were to have stumbled upon it, they would've probably thought it was just another shoebox, but Soarin was sure this was the correct one, for he had labeled it discreetly with a tiny blue sticker on the side that had a smiley face on it. Subtle, but effective, inside laid his second most precious secret, to which he had taken numerous measures to protect. As he lifted the lid off of the box, it was revealed that the contents were none other than a diaper and a shiny Wonderbolt uniform.
Soarin's eyes glittered at his secret possessions. He carefully removed the diaper from its container. He quickly retrieved the necessary goods, baby pony powder, diaper cream, and a soft towel. He then positioned himself on his bed, the towel placed beneath his bottom to help make himself more comfortable and contain the mess from changing. First came the cream, he squirted about a gold bit's worth of cream in his hoof and began to gently massage into his crease, the sensation was enough to stimulate his sheath and slowly but surely, it started creeping out from it's hiding place between his legs. If he had wanted, he could've just kept going with the cream until he climaxed, but what fun would that be? Once thoroughly massaged in, he wiped his hoof and reached for the baby pony powder, while he did like the heady aroma, it still was more for protection than pleasure and he applied a generous amount to his cheeks. Finally, with much eagerness, he pulled out his special diaper and gently placed it underneath his prepared backside. It had taken some practice and he had had a few mishaps in his early attempts in applying the juvenile undergarment, but with persistence and practice, he had mastered the craft and had become quite adept at it. His tail was carefully fed through the special hole designed in the rear, and once the back was properly adjusted, Soarin brought the front over his erect nethers and securing them in the pillowy soft padding. He pulled the elastic tapes to the front and fixed them in place. With his diaper now firmly fastened, he began to massage the plush garment across his privates, the caressing feeling sent euphoric tingling down his spine.
Again, it would've been easy to just to end there and continue fondling himself, but he had to press on and finish what he started. He sat up, his legs dangling off the edge of his bed, his tush pressed against a cottony pillow, with a little effort, he got up, standing completely erect on his hindlegs. While it wasn't uncommon to see ponies occasionally standing and even walking on their hindlegs, very few could do it for any extended period of time, the effort simply being too great on their part, but Soarin was an exception. While wearing a diaper gave him pleasure, standing and even walking while upright augmented the sensation ten fold. It had taken a lot of work and he had the additional benefit of wings to help him whenever he felt unstable, but he had mastered standing, walking, and even shimmying while diapered, which he often did. He sauntered up to his full-body mirror and admired his handiwork. Smugly, he posed for the stallion in the mirror, and was reciprocated by the stallion posing back, his thick diaper with his own cutie mark, a lightning bolt splitting a wave, slightly more pronounced due to his erect penis pushing against it from the inside. After a few minutes of self-admiration, he went back to the box to receive his other hidden delight.
At first glance, it looked like a regular WonderBolt uniform, but on closer inspection, it was clearly distinguishable by the fact it was made from rubbery latex, which was quintessential for its role. Soarin had been foolish enough to have actually used his real WonderBolt uniform when he first started his little project, unfortunately, the material while mildly elastic, couldn't handle to additional bulk and gave way, forcing him to receive a new uniform after coming up with the excuse it had been damaged in the wash. Since then, he had taken the necessary precautions, finding a more durable Wonderbolt outfit was a surprisingly easy task. Cheap, knockoff suits made by fans to emulate their heroes proved to be much more pliable, and securing one by pretending to be a fan and ordering it through ponymail was a simple enough task. Just to be on the safe side, Soarin had worn a fake beard and large spectacles to disguise himself, lest the mailpony recoginize him as a Wonderbolt. Despite this, when he opened the door, the cross-eyed, little grey mailmare looked estatic as she cried, “Oh my gosh! It’s you! I can’t believe it’s really you! Can I have your autograph?!”
Sweat poured from Soarin's brow as he hastily said, “Um, I…I’m sure I don’t know what you mean…” However, before he could finish his flimsy alibi, the mailmare squinted, then pouted, “Hey! You’re not Shia LeHoof! Oh well, here’s your package!” The grey pegasus then merrily went on her way, leaving Soarin feeling an odd combination of immense relief and utter confusion over what had just transpired.
Thinking back, Soarin couldn’t help but chuckle at the situation and then concentrated on fitting both his hindlegs into the suit, then smoothly with a bit caution, pulled upward, the leggings snugly secured themselves around his hooves, ankles, and calves, then came the tricky part, with the skill of a seasoned practitioner, he managed his tail through the tiny elastic hole without damaging it, next came his arms, then each wing and finally the hood, which was a little tighter than what he preferred but definitely tolerable. Like before, he went to his mirror and admired his handiwork. He looked more or less the same as he would in his usual attire, the main and most distinct differences being the glossy shine to his now rubbery suit, and bulge it now supported. It was as though someone had taken a bicycle pump and inflated both cheeks, ballooning his butt to almost triple its normal size, his crotch had increased in size as well, the throbbing erection inside did its part to assist in this endeavor. While he could've remained posing in the mirror, admiring his exaggerated nethers. He had just one more task to complete before he would be satisfied.
By now, the pie had cooled down sufficiently and was ready for consumption. With a slight waddle in his step, Soarin made his way back to the kitchen, enjoying each burst of sensation the combination of velvety diaper cream, plush padding, and rubbery latex offered him. There it stood, just waiting for him, his mouth watering in anticipation. Soarin took the pie in his hooves, after a moment to inhale the rich fragrances of butter, vanilla, cinnamon, and fresh granny smith apples baked to perfection, and dove into it. While Soarin was never one to excel at manners, he had enough modesty to control himself when needed, but now was a time to release all inhibition, where the only things that mattered were the pleasures each of his fetishes bestowed upon him. As he scarfed down the delectable delicacy, his stomach ever so slightly started to bulge out. Soarin, despite being deeply entrenched in his confection, was aware of this and continued, eager as the blue potion he had added earlier was starting to take effect.
While almost all of Equestria had come to recognize Soarin as a successful WonderBolt cadet who worked hard to achieve his merits, it was to the opposite extent the amount of ponies that knew of how Soarin was once rather overweight as a colt. Through his dedication, he managed to shed his former fatness, and become the ideal WonderBolt he was today. However, there were times when he realized that he had missed the ample, softness he had grown so accustomed to. It was through sheer chance that during a mission, he had rescued a baker pony from Canterlot who had the answer to his dilemma. The pony had given him a donut, which was the result of an attempt to create gooey, chewy superstuffed donuts. The secret was a special potion, that when added to any food, would cause it to become incredibly fluffy and delicious, However, to both the baker and Soarin’s surprise the potion also had the temporary effect of massive weight gain, proportional to the amount used. The Baker was shocked and apologized profusely, but after a brief pause a smile spread across Soarin’s face as he realized this had been the feeling he had been missing.
Even now, those same feelings washed over him once more as he felt the suit was becoming tighter across his body, his drastically protruding stomach fighting against the elastic material, but it would not yield, and the rubbery suit contoured itself to adjust to its wearer's new shape. The diaper, which Soarin had also treated with the same magical mixture as the pie had allowed it to swell and adjust itself based on it's owner's size, and it's thickness increased to accommodate Soarin's now dimpling flank, the cream and powder rubbed together quite pleasantly as each cheek filled with ample adipose deposits. The fat began travel downward and Soarin's thighs and calves began ballooning up as well, fighting against the diaper, which kept them apart as it also continued to enlarge as well. While the bottom part of Soarin was continuing to increase in size, his upper body, particularly his chest, started to tingle and with anticipation, he felt his pecs both bulge and rest upon his now rather large stomach as a new pair of soft, squishy moobs. His arms shortly followed, everything beneath the shoulder was engulfed in a great wave of fat, soon the only distinguishing aspect of his thick, sausage like appendages was the crease that once his elbows.
At this point, Soarin had essentially finished his pie in its entirety, licking only the crumbs at the bottom of the greasy pan. His head remain mostly unchanged except for his now marshmallowly cheeks and multiple chins. He put the empty tin down and with the gusto of a kid given free reign in a candy store, began feeling himself all over. His entire body was soft to the touch, but firmly held in place due to the latex WonderBolt uniform, he felt his nether region and the expanded diaper offered an additional softness his body alone couldn't produce. He plopped down on his haunches and began to flail his hindlegs, the friction against soft, fatty legs against plush, poofy padding was almost more than he could stand. Even buried deep within all the layers he had constructed, laid his increasingly erect stallion hood, ready to cum at a moment's notice. All of the WonderBolt's senses were in overdrive and he couldn't decide which of the numerous sensations he was experiencing was giving him the most pleasure.
Suddenly, something strange happened, something that snapped Soarin back to full awareness of himself and his surrounding. Suddenly it happened again, a gurgle, from deep within him. His confusion escalated, he had never experienced this before. Was something wrong with potion? Maybe the pie? The gurgling this time came much more prominently and it was followed up by a buildup of pressure. Soarin, in his current state, could barely move, and despite his best effort, couldn't muster the strength to stand up. The gurgling and pressure continued to increase in strength each passing second, Soarin couldn't barely contain it much longer. Finally, in a moment of utter release, he let go of every ounce of tension within his body and his padded backside become further elevated as the contents of his bowels released themselves into his diaper.
After a moment, Soarin processed what he had just done and felt the warm, chunky mixture between his butt cheeks. It was also then that he also recognized the smooth, slimy texture in the front of the soiled diaper, implying his climax had come. The morbidly obese, latex clad, dirty diapered stallion managed to finally stand on his wobbly back legs, and after moment, realized that he liked this unexpected addition to his fetish. Of course, once he returned to normal, he'd have to figure out cleaning his diaper and suit, but in the meanwhile, he waddled to his mirror and started to flex and pose, while also mixing in the chunky defecation from the back with the smooth ejaculation in the front.
He reflected upon the image in the mirror, a visage of himself that others would consider so bizarre that it was a secret he kept from even his closest of friends on the Wonderbolts. Nevertheless, somehow he knew that despite the potions effects eventually waning and the inevitable return of his slim, athletic physique, the chubby, diapered pony he saw before him was just as a real, equally as much a part of him. The silly, fun, childish, dessert loving adult foal that still had the heart of a Wonderbolt. He just hoped, against all odds that one day he would meet somepony who could love them both.
The End
Author's Note
Hopefully Soarin will find that special somepony who can accept him, and they may be closer than he realizes. 
