This is based off of  lilLilly's picture which can be found here http://www.furaffinity.net/view/13313521/ please support the official artist =) I claim no ownership of digimon whatsoever.

Discovery

It was a typical warm spring day in a Japanese town that shall otherwise remain nameless. In a certain bedroom of one of the many apartments that stood not far from a well-crowded beach, a biyomon was laying down on her human partners’ bed. She’d spent the past year mostly confined to this one room, her partner had school and worried that the digimon would be discovered if she wandered around on her own. On a rainy day, this wouldn’t be much of an issue to the biyomon, after all it was hard for her to fly when it was raining, but on a nice sunny day like today, it was just hard to resist going out and enjoying the world she’d come to enjoy. Out of respect to her partner though, she usually just stayed in the apartment, only leaving the bedroom to get a small snack out of the fridge to keep her energy up, or to occasionally sneak down the hallway to use the bathroom; she was always careful to not make too much noise when she was out and about, even going so far as to time flushing the toilet with the sounds coming from the TV when her partners’ mother was watching it.
Usually as the biyomon laid there on the bed, she’d just take a nap to pass the time, waking up only to use the bathroom or eat, but lately she’d found it impossible to get much sleep, because a new baby was now living in the apartment, and he had quite a good set of lungs to say the least. Biyomons’ partner adjusted to it quickly, but Biyomon had a hard time tuning it out. Couple this with the fact that the nursery was just on the other side of the bathroom, with the babys’ mother constantly having to come upstairs to check on him; and it made every little opportunity to go to the fridge or the bathroom that much more challenging.
So the pink bird-like digimon stared up at the ceiling pondering her situation, the arrival of the new baby had opened the door to 3 problems for her: 1) she couldn’t take her daily naps, 2) she couldn’t leave to go get food, and 3) she couldn’t leave to go use the bathroom.
Just then a thought crossed her mind, in the few times that she’d been lucky enough to peek outside the door of her partners’ bedroom, she’d never seen the baby go to the bathroom, and she’d always noticed one of the older humans carrying a large plastic bag out of the nursery, and how her partner always complained about how horrible it smelled whenever it was her turn to remove the bag, she’d even once heard her mention something like “I can’t wait until he’s potty trained, I hate it when mom has me change his diaper!” Could that be it? Did something called a diaper eliminate the need for a toilet? Biyomon decided to investigate this mysterious object, the other two problems could be solved later, she’d eaten a few hours earlier anyway.
Biyomon quietly jumped down from the bed and slowly opened the bedroom door, being careful to not make too much noise, she quietly tiptoed down the hallway to the nursery, if there was one thing that she did know about babies, it’s that they sleep a lot, hopefully that’d give her enough time to sneak in, find one of these diapers and get out. She kept moving towards the nursery quietly, she got close enough to peek inside, as she surveyed the room she suddenly remembered that she had no idea what a diaper looked like, maybe the baby would know?
She started to slowly go over to the crib where the baby was sleeping, as she did so, she accidentally stepped on one of the baby toys that had been left on the floor from earlier, the toy began to blink on and off in a rainbow of colors and it played a cheerful tune, this caused Biyomon to gasp and the baby began to stir. The noise had startled the baby and woken him up, then the little tot began to cry, Biyomon covered her ears as best as she could, then heard footsteps coming from down below. Quickly Biyomon ran out of the nursery and back into her partners’ bedroom, closing the door behind her; Biyomon pouted and sat on the bed and looked out the window, there was no way she’d be able to find a diaper in there now. The baby kept on crying much to the digimon’s dismay; she finally decided she should just get out of the apartment for a while, then she face-palmed herself upon realizing that she should’ve just done that in the first place, the outside offered solutions to all 3 of her problems.
Biyomon unlocked the bedroom window and flew out of it like she’d done a handful of times before, closing the window behind her. Her thoughts drifted back to the mysterious diaper once again, maybe she could get answers out here, she decided to go to a place where humans were likely to be hanging out in groups, surely at least one baby would be among them. The beach was crowded but too wide and open, someone would see her, as she hovered around, she noticed a flock of pigeons heading in one direction, she decided to follow them, she’d noticed in the past that they always seemed to know how to find humans and food rather quickly. She followed them to a local park, she looked down and noticed a mother sitting on a bench holding a baby, and right behind them was a bush, a perfect hiding spot. She came in for landing and hid inside the bush so that she could watch the two humans without being seen. At first not much happened, although she did think the baby looked rather cute as it drank from a baby bottle. It made her wonder what it would be like to be treated like a baby, her eyelids began to droop as she started to daydream about her partner babying her, it looked like a lot of fun and so relaxing, but she snapped back to reality as soon as she heard the mother say something that caught her attention. “Ok baby, time for mommy to check your diaper” Biyomon watched closely as the mother pulled on the back of the garment that was on the babys’ waist, and then she put two fingers inside one of the leg holes to see if her little darling was wet. The mother smiled, satisfied that her baby boy was clean and dry. The digimon’s eyes were aglow, now she knew what a diaper was, and it didn’t take rocket science for her to determine how to use it, all one had to do was put it on and go when it was time to go. It sounded a bit nasty, but it was an excellent solution to one of her problems.
It was then that Biyomon noticed the bag that was tucked away under the bench, the digimon wondered if the baby had a few diapers that he could spare, she stealthily dragged the diaper bag closer to her and then quietly snuck away with it to a quiet and secluded clearing not far from there. She’d take what she needed and then put it back, no harm, no foul she told herself. As she sat down and rummaged around in the bag, she found a few more garments that looked that looked a lot like the one the baby was wearing. “These must be diapers, alright!” she exclaimed. She took two of them out and set them aside, she figured she’d only need one for now, the other one she’d keep for when it was time to change, she could always get more from the nursery back at the apartment. She’d also noticed some jars inside the bag, the contents didn’t look like anything she’d seen before, but she instantly recognized the word “bananas”, they were one of her favorite things to eat from this world, she also saw a bottle of what appeared to be milk, but the top of the bottle looked funny, she thought about having some of the milk, but since there was only one bottle, she figured it would be missed. Instead she just took one of the jars of mashed bananas and ate it in only a matter of seconds, it tasted exactly like the bananas she knew and loved much to her delight. She then turned her attention to the diapers, she unfolded one and tried to figure out how to put it on, after a few failed attempts to put it on while standing she decided to lie down first. The ground she was standing on felt rather hard and looked uncomfortable, it was then that she noticed the blanket inside the diaper bag, she felt it and instantly loved how soft and cushiony it was, just like the diaper she held in her other wing. She laid the blanket on the ground out flat, then laid down upon it, it felt so soft and soothing, she wriggled around a bit before attempting to put the diaper on again, after toying with it a bit, she learned that the tapes on the sides were meant to hold the diaper up, she got it on and then sat up. It felt so soft and cushiony, much better than the cold hard toilet seat, she rubbed the front and back of the diaper, listening to the soft crinkling sound it made and loving the poofiness of the diaper.
She then stood up, and was surprised at how much it forced her legs apart, this made her giggle, she figured she looked really silly right about now. But then she heard the diaper fall to the ground, she picked it up and tried to tighten the tapes, but despite this, the diaper fell down again. She groaned a bit in frustration and tried to pull it up even higher on her body, but her tail feathers made this impossible. Then she tried to tuck her tail feathers inside the diaper, this did keep the diaper from falling down, but it was very uncomfortable. Then she had an idea, if she could make a hole in the back of the diaper for her tail to go through, then it would stay up and be comfortable.
After taking off the diaper, she unfolded it and laid it on the ground, the back of the diaper facing her. She concentrated and used her Spiral Twister attack in an attempt to burn a hole in the back of the diaper, instead the diaper burned up completely, Biyomon quickly patted the fire out with her wings so that it wouldn’t start a bigger fire, in retrospect she decided this was not one of her better ideas. So she took the one good diaper and began to tear a hole in the back of the diaper with her beak, bits of the stuffing got in her mouth causing her to spit it out in disgust, but this made her notice how absorbent the diaper was, and the bits of stuffing expanded from absorbing her saliva. “Oh, so that’s how it works!” she exclaimed.
Satisfied, she lied down again and put the diaper on, threading her tail feathers through the hole in the back once she was done. It felt great! The diaper was snug and comfy, and she wished she had a mirror just to see how cute she was in her diaper. Her celebration was cut short however, as she’d suddenly heard the baby crying, quickly she grabbed the blanket and put it back in the diaper bag, then she waddled as fast as she could while carrying it back to the spot where she’d found the park bench where she’d found her new diaper. Biyomon blushed thinking how silly she must look waddling like this. She crawled under the bush and slid the diaper bag back under the bench, just as the mother reached for her babys’ bottle. Biyomon stayed there for a bit and watched the mother feed her baby, it made Biyomon a bit jealous, she’d hoped that her partner would bottle feed her sometimes as she lounged about in a diaper; it looked like fun.
After some time Biyomon got bored and decided she should probably head back. She went back to the clearing and got ready to take flight, but a sudden pressure in her gut made her stop, those onigiri (riceballs) that she’d eaten earlier today were about to leave her body. Biyomon instinctively looked around her, hoping to find a nearby bathroom, but then she remembered her diaper; the digimon blushed and smiled a little at what she was about to do. She spread her legs apart and squatted down, her tail feathers went up and the back of her diaper sagged as she messed her diaper. The expanding diaper forced her legs even further apart, as a result she also wet her diaper. When she was finished, Biyomon patted the back of her diaper, perfectly happy with the situation she’d found herself in. She decided that she’d best head home now, it was getting late and her partner would be home soon. Not only that, but her smelly, wet and squishy diaper seriously needed changing.
Biyomon flew back to the apartment with added difficulty, the sagging diaper kind of weighed her down a bit, but she managed to get back to the apartment alright. It was a fun and interesting day overall, she’d figured she could find a way to steal some diapers from the nursery to solve her bathroom problem, and maybe she could get ahold of some more of that baby food, surely it was kept somewhere in the kitchen. But for now, Biyomon cared only about her third problem, and thanks to the fun and exciting day that she’d had, her solution was now at hand, as she yawned and laid down on her partner’s bed, blushing and smiling a bit as her messy diaper squished as she sat down and laid back. As she drifted off to sleep, she dreamed about how much fun it would be to be treated like a baby by her partner, she smiled and sucked her thumb as she slept.
Sometime later, her human partner walked in her room and instantly the smell of a used diaper hit her nose, and her jaw nearly hit the floor when she looked over at her sleeping digimon partner. “Biyomon?!” she exclaimed. The digimon woke up when she heard her partners’ voice, she’d forgotten about the diaper until the smell hit her nose and she saw the look on her partners’ face. “Um…I can explain, but first…could you change me please?...” And the rest is history…