[Futanari, Diapers, Diaper Use, Soiling]

As Humanity advanced, so did the technology that they had at their disposal. And while their vessels grew bigger to allow for mass transit, the vehicles that were once used in excess were left behind. So many small cars, planes and boats that were left to rot in the sun from disuse.

Until one day, when a brilliant man decided that enough was enough. Tired of seeing the things that entertained him in his youth, he brought them new life by injecting them with the ability to stand on their own. And what better way to do that, than to make them into adorable girls?

That was how the world became populated with the vehicles of yore, with their new humanoid bodies letting them blend in with the ones that they had once served. With no hard feelings one way or the other, as some of them were still more than happy to act as vessels for them to board should the opportunity arise.

However, for the smallest of planes that couldn’t handle the strain of having a human riding on top of them, their new purpose in life was not to deal with passengers. But rather, to deal with cargo that still needed to be transported between different locations. Whether overseas, or inside the same country.

Due to the relative size of one of these girls, and the fact that their equipment made them so much smaller than the contemporary planes that once flew through these skies, the ability to deliver items across the world became that much more accessible. Certain private citizens were even able to hire personal plane girls, should they want to ensure a certain delivery speed.

There were just a few kinks that needed to be ironed out, regarding their humanoid bodies’ needs and the complications that arose through traversing from one end of the world to the other. And many of the young plane girls found this out the hard way.

Simply put, when you’re flying through the air at speeds that would break a regular human, you don’t have time to stop should you need to relieve yourself. Whether it’s down below, or out the other end. Both because it’s incredibly rude to just let it all fly out, and if those ‘droppings’ started to fall in a populated area, the complaints would nail them to the cross and prevent them from ever flying again.

That was why plane girls, especially the younger ones, were all equipped with state of the art ‘Waste Disposal Units’. That’s what they were called, but really they were just heavy duty diapers that were impossible for a single plane girl to remove. This degree of security was necessary, so they didn’t end up making a mess all over the place. And with this, plane girls could easily traverse the skies without worrying about a thing.

At least, that’s what their creators assumed. But girls like them, who had plenty of developing interests on their minds, were quick to discover the ‘benefits’ of being padded all day long…

---

“Hhaaaahhh…”

Today, on an otherwise unremarkable sunny day, a young plane girl was busy flying through the air. With her eyes firmly set on her destination, even as she swayed from side to side.

Her name was Lily. Though her frame was young and innocent looking, she was actually made from an older model. That’s why her hair, as jet black as the night sky, had a set of bangs that looked like a rotary blade. Because before she was repurposed for this kind of use, she had to use it to deal with the issue of aerodynamics.

The rest of her body was as lightweight and as streamlined as it could be. No plump areas, not even a fat pair of tits like the other girls who she worked alongside. Just a simple petite girl, carrying as much as she could.

Unfortunately for her, there was just one thing that managed to make her trip through the air difficult. And that thing was nestling between her thighs. In fact, it was the one thing that made her sway from side to side as she flew as straight as she could.

Her Waste Disposal Unit, or her ‘extra adorable and incredibly thick diaper’ as her owner called it, was filled to the brim. As it turns out, being spoonfed plenty of food for being a good girl and an adorable worker didn’t give her the best track record in terms of keeping herself clean during a trip through the skies. It was the specific reason for the size of her pampers too…

“G-Gotta… Gotta keep it in…” Lily muttered as her hair blew along her cheeks, before she nearly stalled as her body trembled. “Noooo, not againnnn…” She muttered, her face turning a bright shade of red as she started to lose altitude.

All while something started to slide out from between her cheeks. A thick, disgusting brown slop. It was all thanks to the last meal she had. If she hadn’t eaten so much, if she hadn’t let her owner absolutely spoil her and make sure she was completely stuffed, she wouldn’t be in this situation.

“I-I gotta tell the mistress that she can’t… she… ahhhh…” The black-haired plane girl muttered as she slowly but surely started to grow blissful, as her incredibly soiled seat filled out with pee in the front. Just enough to make it as soaked as it was soiled, leaving her to sink eeeven further.

Should Lily not correct her course, she was destined to crash sooner or later. And that meant that she’d make all of her packages wet, and then she’d get a scolding from the client and from the mistress, and then… Oh, she didn’t want to think about it. But at the same time, the feeling of her wet pampers was way too nice…

“Heeey!”

The black-haired plane girl snapped back to attention, adjusting her course to prevent further sinkage, as she quickly looked around. Her communications were open, but where was the transmission coming from? Who was calling her, at that?

“H-Hello? Who’s there?” Lily asked, not realizing that she wasn’t flying at her normal speed. Not just because of her prior altitude loss, or the weight of her soiled and soaked diaper…

A brief bout of static poured through her ears, only for a redheaded and red-suited girl to fly right past her, barely turning around with a grin on her face. Despite the dangerous maneuver, she seemed perfectly fine. Signifying what kind of plane she had been made from. That, and the jet engines on the bottom of her feet…

Just looking at her, it was hard to not call her impressive. Whether it was the amazing custom red paint job on her bodysuit and her attached wing units, or her feminine form being exaggerated yet somehow able to lessen the drag. Not only that, but given the bulge in the front of her diaper, she was quite the well-developed girl..

Except… Hold on. There was a skull painted on that bulge. W-Wait, was she about to get robbed by a pirate? There were pirates all the way up here?! Oh no, what was she going to do?!

Lily panicked, her body sinking further, until the red-clad girl grabbed her and prevented her from falling further, using her custom engines to keep them both afloat. “There there, I gotcha.” She chimed, a maternal if a bit cheeky voice leaving her lips. “Don’t you worry. I’m not on duty, you don’t have to worry about your precious cargo getting stolen.”

“H-How am I supposed to trust you?” The black-haired plane girl asked, feeling nervous in the older looking girl’s arms. Even if she was nice and soft and the feeling of that bulge rubbing up against her thoroughly soiled padding felt reaaally good. Like she could just grind against it… But then her mistress would scold her for getting horny around a pirate…

The older plane girl giggled as she patted the youthful pooper on the back. “You’re not. But just this once, let me help you. There’s a little base of mine down below, I can repair you and fix you up… and get you a change for the ‘fuel’ you’re lacking.” She chimed, reaching down below to squeeze that soaked pamper.

Lily let out a yelp, her own appendage spiking with pleasure as she felt the hand squeeze through her diaper. She didn’t even realize she was low on fuel. Maybe that was why she was so soaked. “F-Fine. B-Be gentle.” She asked, as she slowly but surely started to slow down, relying on the older girl to take her to their destination.

Her rescuer smiled as they descended towards her private base, where she could have plenty of fun with the girl…

---

Arriving at the base wasn’t difficult. Especially once they put their abilities together and made sure the landing was smooth, But once the poor girl touched down, the smell of the thoroughly-filled diaper was overpowering. Something that you couldn’t notice when you were far up in the air, but being this close… That was a different matter entirely.

“Wh-Who are you anyway?” Lily asked, nervously shifting around as she took a slow and soft seat on her thoroughly filled diaper. She couldn’t trust her, but at the same time, she had helped her. She had to at least try to be courteous until she could take off once more.

Her rescuer undid her long blonde ponytail, letting her hair reach all the way down to her bulging pirate-themed diaper. “Uni’s the name. I keep girls like you from falling, because you always look out whenever there’s a pirate on your ass.” She giggled, as she grabbed ahold of the skull-shaped sticker on her diaper, tearing it off without a problem. “None of you realize that it’s fake either, so it’s a great tool, don’t you think?”

“E-Eh? W-Wait, you’re not…” The black-haired girl was so unsure of herself, shivering as the older woman crept closer to her. What was she supposed to think? How was she supposed to think? Oh, if only her mistress was here. Then she’d tell her.

Uni laughed at the way she kept on shivering and shifting from side to side. “It’s just a little trick. Don’t worry.” She chimed, before putting her hands on the young girl’s shoulders. “Now, how about I get you a new diaper, and we’ll have a bit of fun after that? You know, as payment for preventing your crash.” She licked her lips ever slightly, the very tip of her bulge growing wet as she spoke.

“I… I-I’m not supposed to…” Lily said, but her cheeks were flushed as bright red as they could be. Her lips were saying one thing, her body was saying another. The latter being rather obvious as her diaper started to bulge on its own. Her own appendage, the grower that it was, had finally made its appearance.

Her rescuer smiled as she grabbed ahold of the latches around the girl’s diaper. Much more powerful than regular tape, they required a dedicated and firm grip to tear open. And since she was used to these sorts of things, it wasn’t hard for her to pull it off, freeing the black-haired cutie from her poopy prison.

“T-Thank you…” The young plane girl muttered as she lifted herself out of her diaper, watching the older girl casually kick it away after using the latches to shut it. “W-What about your own?” She asked, nervously reaching towards it. If she was going to have fun with her, then she should get it off too, and she probably couldn’t…

Uni stopped her as she grabbed ahold of her own diaper… And simply just tugged it down, revealing her arm-sized cock underneath. “Don’t worry. I wear pull-ups. I don’t go up there often, so I don’t need the full treatment.” She grinned, slowly stroking her hand along her shaft as she got into the mood.

Lily watched the shaft, her own rod quickly growing erect. This was another thing that was special about plane girls like them. They had both sets of genitalia. Because while they weren’t certain if they could breed, their creator didn’t want them to lose out on the chance to experience sex in all of its glory.  That, and it worked as a great way for two plane girls to share fuel, should the need arise.

“You want it?” The blonde girl said as she slowly let her hand leave her shaft, before beckoning the girl to come closer, laying down in the process to let her have a better angle. “I’ll give you all the fuel you need. You just take it at your own pace.” She chimed. The best way for plane girls to bond was to be comfortable with one another after all.

The black-haired girl, whose cock was about the size of her thigh, nervously nodded as she came closer. Though her pussy was starting to drool, she knew that if she took it in that hole… She wouldn’t be getting the fuel she needed. So she positioned her other hole, the same that she let waste out through, right above the hole. “Y-You’re sure your fuel won’t cause problems for my tanks, right?”

Uni didn’t give her an answer, preferring to just thrust her cock up ever slightly, sinking her head between those cheeks and pulling her down in the process. The sound of her moaning was outright delightful, the younger girl trembling from the shaft inside her. “Ssssh. Don’t worry about it.”

Lily let out moan after moan as she sank further down, feeling the shaft spreading out her poor waste pipe. Her mistress had done this to her before, but this was a thicker rod. She just hoped she wouldn’t be ruined, because if her mistress couldn’t get the same sort of pleasure in the future, then…

“H-haaah!” She cried out as her train of thought was once again cut short thanks to a certain blonde wrapping her tits around her shaft, giving her cock plenty of adorable kisses. Because what better way to make sure she was enjoying the experience than to milk her cock, just like she was doing with her ass?

Uni grinned as she thrust upward while pushing her breasts downward, giving both the waste pipe a taste of more of that wonderful cock, while also caressing the girl’s cock at the same time. By pleasuring both ends, there was no chance of her feeling neglected. Whether above or below.

Lily let more and more moans slip out of her mouth as she was on the verge of having her eyes roll into the back of her head. It felt that nice. She wasn’t sure if she could actually get back into the air after this, her legs feeling like they could give out at any moment after this treatment. Whether from the anal pleasure or the penile kind…

Both of their moans started to twist together as they climbed higher and higher, their orgasms getting closer and closer. Better to cum together than to cum apart. And the more old fuel the young plane let out, the more she could be refueled.

The first to cum ended up being the black-haired girl, whose thoroughly filled ass tightened as hard as it could around that mighty shaft. All while she thrust her hips more and more forward, letting the older girl wrap her lips around the sensitive head and catch it at the same time, suckling on it to make sure she got all the ‘fuel’ that leaked out from the tip.

Once Lily had reached her climax and began to fill up her stomach with plenty of that sticky stuff, it was Uni’s time to let loose. With one final thrust to make sure she was as thoroughly filled with the meat as she could be, she had her cum erupt from the tip of her cock and quickly fill up her stomach from the sheer strength of her ejaculate.

“S-So much!” The black-haired girl cried out as her own balls emptied, while her stomach started to fill up. It was a little extreme, honestly. Feeling all of that cum filling her belly, to the point where it was starting to bulge out from the sheer amount stored inside it. And at the same time, it felt nice. With this much ‘fuel’, she should be able to speed to her destination and get back before dinner…

The blonde girl licked her lips as she finally finished injecting all the ‘fuel’ that she could, her cock turning completely limp inside that incredibly tight hole. “Satisfied?” She said, the poor girl’s cock having slipped out of her mouth as she panted. Gasping for a bit of air as well, while her partner slowly rose up…

“Y-yes. Absolutely.” Lily said, her belly sloshing around as her cock drooled. “W-Would you be kind enough to help me a little with my Waste Disposal Unit, miss Uni?” She asked, a big blush on her cheeks. All while a bit of that cum pumped into her rear started to leak out.

Uni nodded as she got up herself, her cock slick with her own juices. “You need anything besides that?” She asked, patting the smaller girl on her head.

“N-No, not at all.” She muttered, the short girl doing her best not to look at the helpful girl’s beautiful face or amazing chest, shivering as her cock slowly grew hard once more.

The older girl let out a laugh, helping her back into a fresh diaper, not nearly as thick as her regular ones, before waving her off. All while keeping that smile on her face, happy to have helped yet another adorable girl. Now, to wait for the next one.

Lily let out a sigh as she once again returned to the skies. Being up here was so relaxing. And now that she was freshly padded, she… she…

Her cheeks flushed red as a cramp started to pour through her body, before she let out a whine. As it turns out, getting filled with that much ‘fuel’ wasn’t a good thing, as the poor girl started to fill her brand new diaper up once more, the poor thing sagging as it tried to keep it all inside.

“Whyyyyy…” The black-haired plane girl whined as she tried to keep her pace, the weight of her diaper making her drift from left to right once more.

She sighed. At least she’d keep herself warm during the trip, and if she was lucky… Maybe Uni would see her on the way back, and…

The bulge in the front of her diaper thickened as her thoughts started drifting, the blush remaining on her cheeks as she continued flying through the skies. With anything but her task on her mind.

Her mistress was sure to deliver her quite the punishment for all the fun she had gone through...