Upon entering the loft bedroom on the right of the stairs Twilight was greeted with an unexpectedly normal situation. Pinkie was simply laying upside down on her bed staring at the celling with her typical wide smile.

After a few odd seconds where the pink pony simply kept looking up at the ceiling without any acknowledgment of Twilight's existence Pinkie Pie suddenly turned herself over and hopped off the bed.

“So, you brought my delivery from Rarity?” Pinkie asked with simple curiosity as if her earlier non-sequitur had never transpired at all.

“I uh, well yes, I guess I did” Twilight said fumbling out her reply as she levitated the saddlebags off her back. It was a relief to have them off her not so much because of any weight they had which was quite little in fact but simply because she had grown accustomed to not having needed them so much in the years since her ascension and now they felt strange and slightly uncomfortable against her wings. Perhaps this was why Pegasi as a rule generally did not use the things. Though she had seen Rainbow Dash do so on occasion.

Twilight was distracted from her musings on Pegasi and their preferred methods of cargo transport by the rustling sounds of an excited earth pony digging into the contents of the saddlebags Twilight had brought. Out of the left-hoof bag came what looked like a collection of various items including but not limited to a pair of what looked to be travel brochures a couple small square samples of a very smooth and shiny material in pink, black, and grey and a small wrapped box, contents unknown.

Twilight decided it was better for her sanity to simply sit and watch the pony in front of her than to risk getting involved in another conversation. Having hoofed around at the contents of the first bag while excitedly mumbling to herself Pinkie moved onto the second and when she opened it and extracted something large and wrapped tightly in a plastic bag or two, Twilight couldn’t be sure, her smile became and grin and she hurried over to the front left corner of the room.

“Just what I always wanted!” exclaimed Pinkie as she carefully laid the wrapped item out on top of the table located there. A changing table Twilight now saw. It wasn’t a new addition, it had been there for quite some time ever since the Cakes had had their twins several years ago. How old would they be now? Twilight asked herself, four? No, five years? Surely no more than-

This time it was Twilight’s sense of smell which brought her back to the present. It was a now very familiar smell, one which she had recently had good practice in getting more acclimated to. The smell of a very well used diaper began to permeate the room and it was coming from the now unwrapped object that Pinkie Pie was removing from its wrappings.

Twilight sat up in surprise as she stared at the changing table and what lay on top of it. Rarity’s used diaper, as unmistakable to Twilight as her own wings lay untapped and exposed on the soft mat on top of the changing table, the insides of which were completely coated with Rarity’s thick brown waste from front to back. The diaper smelled even stronger now than it had before as its contents were mostly near on a day old by this point. Twilight wasn’t sure whether to be turned on or repulsed at this new development.

It became swiftly apparent to Twilight however that Pinkie Pie had no such reservations as the smiling pony dipped a hoof tip in the mess, swirled it around and then in one swift motion licked it all up and swallowed.

“Wow Twilight! This tastes just like Rarity, which makes sense, since it’s Rarity’s!” Pinkie giggled while licking her lips. “Would you like some?”

How could she possibly know what-

“Um, hehe, No Pinkie, I think I’m fine… Twilight said again not sure if excitement at seeing this was a good thing or not.

“Your loss Twilight! It tastes just like dwarf blue iris blossoms in March!”

Twilight’s left eye twitched.

While the Alicorn tried to restart her stalled mental engines the pink mare had hopped over to the far side of the changing table and was busy rooting around in the diaper pail located there. As Twilight looked on Pinkie fished out a disposable diaper which while smaller and less…well decorated than Rarity’s had been equally well used.

“Huh? Where did that come from?” Asked Twilight, her mind finally catching up with events. Who’s been using this place? That diaper is too small for y-“

“Oh this? This is Pumpkin Cake’s! I let her wear diapers when I babysit her on the weekends.” This was her Saturday diaper.” Pinkie said as though discussing bath towels. “I think she secretly likes them.” Pinkie whispered as though there was somepony to overhear.

“She must,” thought Twilight ruefully eyeing the smeared about contents of the plastic undergarment.

“Wait, ‘Saturday diaper?’ You mean she only wore one?” Asked Twilight with confusion.

“Well, she never wants me to change her, so I just gave up and let her stay in it until its time for her to go home,” shrugged pinkie. Besides, what kind of pony would I be if I didn't allow a filly to be as happy as possible?”

Twilight considered the irony that had such a statement been made in reference to nearly anything else it would have come across as responsible and kind. Under the current circumstance though…

Before Twilight could formulate an intelligent response to this the pink mare turned herself around and hiked her tail up giving Twilight a very full view of the pink furred earth pony’s thickly rimed plothole and wide full marehood.

“Besides Twily, with her leaving her used diapers behind I get to keep them and do things like this!”

With a forehoof Pinkie maneuvered the diaper around and under her tail and with a wet squelch she slapped the mess coated young filly’s diaper right up between her legs where she proceeded to rub its light brown slick contents all over her puckered anus and wet slit apparently putting special attention into working it into and between her pussy lips as much as possible.

Twilight stood there rather shocked, first Rarity and now Pinkie Pie? Who else might possibly be into… probably best not to make too many assumptions she decided, it was best for her state of mind to not go around seeing hidden diaper lovers in everypony she knew. Besides out of all her friends Pinkie Pie was the most likely to get involved in a habit as weird and filthy as this one. Rarity though…that was still a genuine surprise.

“Mmm…so poopy…” Moaned Pinkie Pie as she continued to grind her crotch into the sloppy day-old messy diaper.

It was one thing, Twilight thought, to stay for a while in your own messy diaper, but to play in somepony else’s… Then again, was what Rarity had done to Twilights messy slit with her tongue really any better?

With an unexpected sharp, short scream Pinky’s shuddering body came with force into the messy diaper being held against her marehood. Twilight for her part was rather caught off guard; the mare must have been considerably more horny than she had let on. Instead of making any sign of wanting to clean herself up as Twilight expected her to the pink mare instead bounced happily over to the changing table and jumped up onto it all the while keeping her tail lifted high in the air.

Twilight had to admit to herself that she was becoming a little excited seeing all the ‘fun’ Pinkie was having despite the awful smell. With absolutely no hesitation Pinkie proceeded to plop her backside down in the veritable sea of squishy brown mess, which was the interior of Rarity’s used diaper. Pinkie closed her eyes and rocked back and fourth obviously enjoying the sensations of another pony’s waste squishing against her sensitive places.

Opening her eyes Pinkie called over to Twilight. “Hey Twilight do you mind giving me a hoof here?” Pinkie asked motioning to the diaper tapes. “Unicorns always seem to do it better, what with the magic and all.” Pinkie said with a trace of annoyance on her face.

Having the pink pony say something to her directly finally got her moving again away from the spot she had occupied since arriving in the room.

“Um, ok,” Twilight said slightly uncertainty. “You just want me to pull it up for you and tape it? She asked.

“Yeppers! Isn’t this fun Twily, Rarity says she has given you a few ideas of her own. Maybe you can try some of them out soon!”

I think I got more than just some ‘ideas’ from Rarity Twilight thought with some amusement, though she said nothing. Twilight had just taken hold of the tapes with her magic when Pinkie thrust out a hoof at her.

“Wait! Stop, Silly me, I nearly forgot! In the righthoof drawer open it, please!

Twilight proceeded to do so. Inside among some random items like tissue paper and some filly’s mane clips there was what appeared to be an icing bag. Sure, Twilight was still technically in a bakery but certainty not the part where such things ought to be stored.

“Is um, this what you wanted?” Twilight asked with a quizzical expression while levitating the confectioner’s tool into the air in front of pinkie.

“Yes, yes, definitely!” Pinkie Pie grabbed it out of Twilight’s magic field and in a rather awkward move for a pony to achieve managed to stand partially upright and use her fore hooves to hold open the top of the bag and position it under her tail. With little globs of brown mess falling to the open diaper below in little splats, Twilight looked on at Pinkie with genuine curiosity.

With an oddly happy sounding grunt pinkie pushed hard and out of her anus poured a thick mass of slightly runny brown muck, which seemed to go on for a surprising amount of time, overfilling the icing bag and spilling into the already overfull diaper below. With a sigh Pinkie squeezed the top of the bag closed forcing some more of the sloppy mess over her hooves as she plopped herself back down into the diaper with a soft splat.

“Ahh, much better…now for the best part!”

“Um, Pinkie, what are you-“

“Shhh! Just watch a master at work Twilight!” I might give you an idea or two myself! Hehe!

Again Pinkie Pie managed to surprise an alicorn who thought that she had experienced and enjoyed being as dirty as a pony could reasonably get. Though with hindsight Twilight really shouldn't have been so surprised since ‘reasonable’ was rarely a term used in the same sentence as the name Pinkie Pie.

As Twilight watched, cowed into silence for the moment, Pinkie Pie lined up the long plastic nozzle of the bag with her vaginal opening, for the moment hidden underneath a slick coating of mare poop, and with confidence born of practice deftly inserted it in as far up into herself as it would go. Pinkie closed her eyes and shuddered, though not as much as she did when upon having sealed the icing bag she gave it a forceful squeeze as one would when quickly decorating a cake and pressed all the squishy poop it contained out of the bag, down the long tube and deep into her vagina, practically in her womb.

And here Twilight had thought Rarity to be a depraved mare, even more so than Twilight herself. Yet before her sat a pony who had essentially devised a makeshift dildo which would cum great quantities of her own poop deep inside herself. Twilight’s intellectual appreciation of Pinkie’s own inventiveness nearly overcame her concern for her friend’s wellbeing, though not quite.

As Pinkie rocked back and forth in the squishy waste of another mare having removed the now empty icing bag from her insides Twilight decided to voice her concerns. After all it was one thing to smear her poop around where it could be washed off but she wasn’t sure how a pony could easily go about cleaning herself up ‘in there’ especially an earth pony whit no real capability of controlling active magicks.

“Hey, Pinkie, are you sure that was ah, a good idea?” Asked Twilight staring at the mass of brown slime that was Pinkie’s crotch. I mean, pee is sterile and all but solid waste tends to have lots of-“

“Aw Twilight! I didn’t know you cared!”

“Of course I care, I’ve always-“

“Hehe, don’t you worry! I’m an earth pony remember, strong i-“

“Immune system, right I know but still… Twilight continued.

“If it makes you feel better Twilight, I’ve done this many times and it’s never caused me any trouble. Well except that some always tends to keep on leaking out for several days afterward… Really annoying because when that happens it makes me horny… and then I have to masturbate… and then I have to clean myself up again…which is a lot to accomplish between helping different customers...”

Twilight’s left eye twitched.

“Haha, you should see the look on your face. You are so adorable Twily! I’m actually very good at cleaning myself up! Any baker worth their batter has to be! Now, will you pleeeeze help me with this diaper?”

Twilight sighed to herself seeing that there was nothing really to be changed about the situation, Pinkie Pie had her vagina full of her own scat and was determined to enjoy it. Putting on another mare’s messy diaper around it wouldn’t make things any worse at this point. So with care she pulled the thick sloppy diaper up around the pink pony and resealed the tapes, which were still quite sticky and held the diaper tight against Pinkie.

As soon as twilight released her magical hold on the diaper Pinkie rolled onto her back and let out a relaxed sigh.

“Mmm, I’m peeing Twilight, wanna feel?”

“I, uh, sure,” Twilight said failing to come up with a good excuse for not doing so. Laying a hoof on the front of Rarity- Pinkie Pie’s diaper Twilight could feel and hear the soft hissing of fresh urine entering a diaper. Despite her reservations Twilight couldn’t help but feel happy for Pinkie who was laying back with her eyes closed enjoying all the sensations which came with wearing another pony’s- a beautiful pony’s poop filled diaper. Twilight was beginning to understand to some degree while watching Pinkie the intense stimulation she would be feeling knowing she was essentially bathing her nethers in another pony’s poop. And besides no matter that it was completely discolored now and beginning to leak the diaper really did look good on Pinky Pie.

The end of her stream of urine and the sound of pee dripping onto the floor brought Pinkie out of her state of utter relaxation.

“Oop!” Pinkie said looking over the edge of the changing table at the brown splatter of dripping urine mixed with poop. “Time for the other drawer!”

‘The other drawer?’ thought Twilight, great what now? However this time the action of getting into said drawer was not left up to Twilight who found herself being shoved out of the way by a pink mare who was quite suddenly not on the changing table.

As Twilight watched on Pinkie pulled out a garment made out of a black shiny material. As it was unfolded Twilight quickly determined it was a body suit of some kind, though obviously not the kind that one did any real work in.

“Latex, Twilight! It’s such fun to wear! Said Pinkie as she struggled into the thing, which seemed to be a bit difficult due to its tightness and elasticity.

“Latex?” That sounds familiar… but where-“

“Ask your foal sitter Twilight! She knows a lot about… A lot!” She’ll help you out!

“My foal sitter?” You mean Princess Cadance? What does she know about l-“

“Just ask her silly!” Pinkie interjected having now won out over the garment- a body suit that left only her head and hooves uncovered. Well and her tail remained free as well.

Twilight had to admit it was a rather…flattering thing for a pony to wear and there was no good way to hide a diaper underneath it. The bulge was rather obvious, though the shiny black latex did an admirable job of making it effectively impossible to determine what state the diaper was in.

“Well, thanks for all your help today Twilight! Its Pinkie’s nap time now and without that I may become cranky!” Good afternoon!

With that the sleepy pony plopped herself down on her bed and after a few wiggles brought on by the feeling of Rarity’s poop squishing itself up and out of the top of the diaper and into the latex body suit not to mention the wonderfully full feeling her vaginal passage gave her being as full of her squishy muck as it was she stretched out on her stomach and fell asleep before Twilight’s astonished eyes.

“But what about…” Twilight found herself saying out loud

Instead of finishing her sentence the Alicorn decided that as strangely as it had come on this was her chance to escape all this craziness and get home before something else happened to upset her already precarious mental equilibrium.

Twilight couldn’t help her smile as she softly shut the door on Pinkie Pie’s bedroom and the sleeping very, very messy pony within. Her smile only grew as she headed out of Sugar Cube Corner. Perhaps Pinkie was right, Cadance was the Alicorn of Love after all and even though Twilight had been intimate with the beautiful young princess on many occasions their activities had always been of a very standard nature rather lacking in things that may be described as ‘kinky’. Though, Twilight recalled with fondness, Cadance did seem to have a thing for tight thongs and horn play and liked to stick hers in very inappropriate places. And besides Twilight was sure that Cadance was an expert on just about every possible fetish a pony could think of weather or not Cadance actually enjoyed any of them herself.

********************************************************************

“See you later Twilight! Oh and tell Pinkie Pie that I expect to be repaid in the future.” Rarity called out to Twilight, smiling to herself as she closed the door.

Turning around from the front entrance Rarity hurried back up the stairs to her chamber intent on making sure that everything was in proper order before her client arrived late that night. It simply wouldn’t do to have a messy bedroom when a paying customer arrived seeking her services. After all she still had an image to keep up. Well, for most ponies at any rate.

Rarity went around with her horn alight straitening, tucking, folding, and brushing all the things she could think of. She also closed the window Twilight had apparently opened up to air out the room. Rarity decided she would find a way to thank the Princess for that at some point.

It was when she opened the door to her bathroom that a decidedly strong smell assaulted her. Of course she thought, Twilight’s diaper. 'I told her to leave it here didn't I'. Well, she thought looking around the rest of the bathroom, aside from the extremely well used diaper lying open on the floor. Twilight had done a remarkably good job of cleaning up after herself. Rarity was simply glad that Twilight hadn't taken the time to question the unicorn on why Rarity had let her simply leave her diaper in the bathroom which would of course cause her more 'work'. Rarity was not quite prepared to explain to Twilight just how much she enjoyed wearing other ponies used diapers. Twilight of course, would by now have some idea that Rarity was willing to interact with her diapers but she would not have any idea just how many other diapers Rarity had worn, including the used diapers of a number of fillies around Ponyville and Canterlot.

Grabbing the soiled diaper in her magic Rarity turned and headed out of her suite and down the stairs. Now that she was content with the level of cleanliness of her rooms she really only had one goal in mind for the rest of the day and that was to get a good start on the design and production of Twilight’s custom diapers. She really did feel a bit humbled at the fact that she had the chance to design diapers for another princess, a fact that Twilight needn’t know anything about just yet. The Princess of Friendship really had looked amazing in her diapers and perhaps provided the opportunity for Rarity to do her best work ye-

Rarity slowed from her previously rapid pace towards the back entrance to the boutique and came to a complete stop. She brought Twilight’s mess coated diaper around in front of her and gazed at it in increasingly excited thought. This diaper was smeared from the top of the front to all around the tail hole in back with a thick layer of alicorn poop and its padding was dripping full of her beautiful urine. This was exactly the situation she would be designing Twilight’s diapers to be able to deal with and not only that but here she had the best example of exactly what it was Twilight could do in her diapers. Perhaps she could even do more if giver more time.

Rarity was a pony that thrived on inspiration. It was how she made her quite successful living as a fashion designer after all. And here held in her magic was some of the best inspiration she ever could have hoped for, delivered really quite by accident. Biting her lower lip in anticipation Rarity spun on her hoof and headed straight into her design studio. As soon as she passed through the entrance she closed and locked the door behind her with alacrity. This was not a day for Sweetie Belle to be allowed to come barging in. Rarity had worn diapers around her little sister in private and even wet them a time or two in her presence, ostensibly for the sake of keeping the younger filly from feeling ashamed about what she did in her own diapers at night even though Rarity was beginning to be certain that Sweetie Belle wasn’t really as ashamed as she pretended to be. But what Rarity was planning would simply be a much too difficult thing for her to try and explain to her sister at this point.

With her heart beating more powerfully in her chest Rarity laid Twilight’s diaper out on the floor and stood over it with a wicked smile creeping up her lips. She lowered herself until her now dripping wet marehood stood just an inch above Twilight’s thick brown mess. Was she really going to go through with this plan? Yes, Yes she was, no more hesitation could be allowed. And with a nod of her head in personal confirmation of her dedication to her desires and work. She squished her crotch down into the thick, rather cool now, gooey mess as hard as she could. It immediately coated itself all over her marehood and anus and everything nearby getting smooshed into her newly cleaned white coat.

A low groan escaped her lips as she slid her hot pussy back and forth in the thick brown slime while taping the diaper tightly up around her waist with its top just coming up over her belly button. This was disgusting, this was repulsive, yet this was heaven. She knew that a few other ponies did this sort of thing. Pinkie Pie immediately came to mind. But she had never before gone so far as to actually wear another mare’s icky diaper about herself. Why hadn’t she? A part of her asked. Twilight was hardly the first mare to leave a messy diaper behind at the boutique. Sweetie Belle herself had done so on multiple occasions. Yet she had never really had a desire to do so. Perhaps with Twilight’s diaper she had been able to overcome some internal barrier? Whatever the case she was happy she had tried it here and now and in a way maybe that was for the best. After all she could hardly imagine a better way to begin wearing other mare’s messy diapers than by wearing one used by an Alicorn Princess of all the pony subspecies.

With a contented sigh Rarity stood up feeling Twilight’s mess slide around wonderfully between her legs as she trotted over to her workbench. Upon reaching her stool she smiled, plopped herself down with another groan of pleasure, and pulled out her preliminary notes and designs for Twilight’s diapers. She grabbed her favorite drawing pencil in her magic and spreading her legs she began to pee and sketch.