Limestone's Lesson

“WHAT?!?”

Pinkie Pie and Marble Pie stood with equally shocked looks on their faces. Their eyes and muzzles were wide-open as they pointed right at their sister’s smug grin. Limestone didn’t seem to show any embarrassment or worry as she stood before the two on her hind-legs; of course, that was most likely because she knew she wasn’t the one about to wear the poofy pieces of padding in her hooves.

“You heard me,” she said with utmost confidence. Even as her sisters’ stunned expressions began to blush profusely, she remained diligent as she motioned towards the changing pad. “You left ME to do all the work outside, so it’s only fair you two face the consequences.”

Pinkie’s eyes repeatedly darted between her sister’s imposing stance, and the bathroom door only a few feet away. “Uhhh, w-wait a minute!” Before Limestone could get the chance to stop her, the pink mare rushed towards the door with her fur standing on end. But alas, as soon as she grabbed the knob with both hooves, Pinkie gasped in a panic when she realized it was locked. She tried yanking back on the knob several times to no avail, which caused her hind-legs to bunch together and tremble upright.

“Mmmphhhh…” Marble Pie blushed even deeper, and tried to bite her lip in an attempt to quell her own building feelings of pressure. But much like her sister, who was squirming badly and desperate to unlock the bathroom door, Marble whimpered and tried her best to keep her legs clenched inward. Limestone just smirked while standing in wait, admiring how badly the two were struggling already. And since she was standing between her sisters and the stairs, she wanted to make sure they didn’t try to leave unprepared.

“I also locked the downstairs bathroom as well.”

Pinkie and Marble gawked back at their sister, but neither of them could say much in response to her unchanged grin. “So unless the two of you want to have a little accident, I recommend you get these on pronto~”

“W-W-WAIT A MINUTE!” Pinkie turned around to face Limestone with a shocked and upset glare. “L-Limestone, come on! This isn’t funny!”

“I didn’t say it was funny,” she replied with a lighthearted shrug. “Do I look like I’m laughing?~”

“Nnnnnghhh…” Marble Pie’s head hung down as she groaned to herself needily. Her hind-legs pressed in even tighter together, leaving her quivering in an obviously dire state. Pinkie could only take seeing her sister’s squirming for a second before looking away, since her own building pressure was causing her hooves to shuffle against the hardwood floor. Neither of them wanted to admit what they needed to do, but they could tell that Limestone knew clear as day already. Unfortunately, the idea of complying with her method of “punishment” felt far worse than just holding it in for the time being.

“P… P-Please, Limestone…” Marble had to lean up against the wall while trembling like a fallen leaf. Her knees were wobbling badly, and her tail was tightly tucked between her tensed legs. “I… Idon’twannadothat…”

“Well, I didn’t want to pick up both of your chores. Especially because of a little milk-binge.” Limestone stared daggers back at Marble, her expression more disappointed than anything. “Honestly, I would’ve expected that from Pinkie, but not you.”

Even with her body twitching badly, Marble Pie could only hang her head in shame. Pinkie Pie groaned more angrily, and tried to storm up towards their sister. “Okay, SERIOUSLY, Limestone?! I know you’re upset, but that doesn’t mean you have to punish BOTH of u--OOFFF!!!”

Before she could finish her ranting, or even get the chance to apologize to Limestone face-to-face, Pinkie Pie was picked up with disturbing ease by her sister. Limestone effectively got the pink mare thrown onto her back, right on top of the changing mat. Pinkie groaned and struggled against her sister’s grip, but the seasoned rock-farmer had considerable strength against the pastry baker. Pinkie yelped out the moment Limestone used one of her rear hooves to nestle between her legs, spreading them apart and making the pressure in her bladder more immense.

“Aaahhhh!!~” Pinkie’s back reeled up from the changing mat, and her blush grew heavier from the growing pressure she was feeling. Limestone used one of her hooves to hold Pinkie’s forelegs over her head, which kept her from trying to pull herself up. She used her other hoof to press down ever-so-slightly against the bottom of Pinkie’s stomach. Due to how much milk she drank several hours ago, only the tiniest bit of pressure was needed to make her tense up against Limestone’s grasp. Her hind-legs squirmed and fidgeted like mad, but the hooves merely skidded against the hardwood floor without any grip. And all the while, Marble Pie just stared with fearful awe at how effectively Pinkie Pie was subdued. “P-P-Please, Limestone! Don’t… D-Don’t push me there!!!”

“Oh, really now?” Limestone smirked more devilishly, and she kept her hoof faintly pressed against the pink mare’s stomach. Pinkie clenched her eyes shut and let out a strained groan, while her hind-legs crossed tightly together to keep herself stable. Limestone kept the pressure unchanged for a few more seconds, and waited until Pinkie stopped grunting to speak firmly. “Now then… do you want to keep fighting me, or are you going to take your punishment like a big girl?~”

“Nnnnnghhh…” Pinkie Pie glared up at her sister with a pained scowl, and had to take a couple breaths through her nostrils. Marble Pie tried to subtly move towards the bathroom door, but much like her sister, she was thwarted by the knob remaining tightly locked. She lurched down for a moment with another heated sigh, and stared back at the other two to see what happened next. Pinkie eventually closed her eyes so she could breath out calmly, and finally relented with a small nod. “... f… f-fine…”

“That’s what I thought~” Limestone finally let go of Pinkie’s stomach, as well as her forelegs before positioning herself between her sister’s legs. She used her immense strength to easily grab both of Pinkie’s ankles in one hoof, causing her to groan out and writhe against her grip. Marble watched in stunned silence as her sister got Pinkie’s backside lifted up from the mat with one hoof, while the other unfolded one of those diapers to lay underneath her. As soon as Pinkie’s rump was lowered onto the plush white padding, Limestone pried apart her legs so she could fold the front of the garment over her nethers.

“Nnnnnnghhhh…” Pinkie couldn’t even look down at herself, and covered her face with both hooves in embarrassment. She was blushing heavily with dread as Limestone got the padding securely wrapped around her waist, with the tapes applied to the sides without any issue. As soon as Pinkie was fully diapered, Limestone turned to face Marble with a firm stare.

“You’re wearing a diaper too,” she commanded with a stern voice, and a slightly vindictive smile across her muzzle. “And until both of you use them in front of me, they’re not coming off~”

“WHAT?!?”

Once again, Pinkie and Marble stared up at Limestone like she just said the most insane thing imaginable. Pinkie may have already been padded up, but she gawked at her sister’s “punishment” in shock and disgust. “Y-You want us to… t-to USE them?!”

Marble’s head lowered in an attempt to hide her paled expression, but she still tried to mutter out, “You… Y-You mean, like…”

Limestone didn’t wait for her to finish that clarification, and merely nodded at both of them smugly. “Well, what do you expect to do in diapers? If you two don’t want to take responsibilities like adults, I don’t expect you to go to the bathroom like adults either~”

Before Pinkie could get the chance to pull herself off the mat, Limestone reached into her bag to pull out a secondary item of protection for both of them: a pair of see-through, plastic shorts with elastic cuffs. “And just in case there’s any leaks, I expect these to be put on as well~”

Limestone began to slide the plastic pants up Pinkie’s squirming legs, while the mare herself whimpered with a worried grimace. While Pinkie was given that second later of foalish protection, Marble reached down to pick up the unused diaper laying beside her sisters. She blushed upon feeling how soft and poofy the plastic was against her hoof. “Oh my gosh… Wh… W-Where did you get these from?”

“They weren’t cheap, I can tell you that.” After rolling Pinkie Pie over for a split-second, which resulted in a loud click to get the pants secure, Limestone helped her sister up so she was back on her hooves. “Seriously, you would not believe how expensive adult diapers can get. Unless you get the cheap medical brands that barely work, each of these pairs cost like, five bits apiece!”

Pinkie’s muzzle was quivering when she finally stood back upright, her hind-legs notably spread a bit wider while so much plastic padding was bunched between them. The diaper was bright white beneath the pants’ transparent plastic, and thick enough to make it impossible for her to walk normally. Marble’s fearful look intensified when she saw the end result of Pinkie’s padding, knowing that she was next in line. “Wh… Why do you have them?”

Marble’s question prompted Limestone to glance back at her, while she and Pinkie just stared back in wait for a response. Limestone didn’t seem too embarrassed to admit with a shrug, “Well, let’s just say that Doctor Elderberry’s ‘Regressive Relaxation Therapy’ has worked wonders in keeping my anger in control.”

“Nnnnfffff…” Pinkie glared at her with a withheld groan, looking like she was about to blow up at her for such a claim. But considering what she was wearing around her waist, not to mention how badly her bladder was swelling inside of her, she was barely able to keep her composure in check to even speak.

“Now, come on!” Limestone pointed to the mat authoritatively, and stared Marble down with an annoyed grimace. “I don’t want to throw YOU onto the mat too! Just get it on so we can get this punishment over with.”

“NNNGHHHH!!!” Pinkie shouted out angrily, “Limestone, I am NOT going to use this diaper!”

“Hmph~ Well, we’ll just see about that…” Limestone paid no heed to her sister’s pissed-off sneer, and watched with a satisfied smile as Marble timidly walked towards the mat. Unlike Pinkie, who could barely stand in her diaper while her knees were wobbling, Marble Pie shivered with a blush and willingly laid on her back atop the mat. She didn’t give any resistance when her sister got between her legs, and lifted her up by her ankles. However, Marble still groaned weakly when she felt the unfolded diaper being laid underneath her rump, before Limestone lowered her back down and got the padding securely wrapped in place.

“Just a few tapes here and there, and… perfect!” Limestone grinned in satisfaction by the time Marble was diapered like their sister. She then got the second pair of plastic pants out of her bag, and began to slide them up Marble’s legs. “And if it means anything, I promise I’ll get you two cleaned up after you do it~”

Limestone gave a cheeky wink after that promise, which made both of her sisters wince uncomfortably. While the pants were being secured in place, Marble waited until she was rolled onto her stomach to ask, “W-Wait, do… do you seriously wear these for therapy?!”

Given how wide-eyed Pinkie was staring at Limestone, it seemed that she was wondering the exact same thing as Marble. Once again, Limestone just shrugged indifferently after securing the pants in place with another click. “Well, it works… I won’t try to lie and say it’s for everypony, but I’m not one to deny its results~”

She helped Marble back onto her hooves, with her hind-legs also spread apart with all the white plastic bunched against her nethers. Marble and Pinkie were left standing side-by-side, with their blushes as notable as the thick padding wrapped around their backsides. Limestone took a moment to grin at the two smugly, happy to give her sisters a well-deserved taste of humble-pie. However, she was also quick to sigh before adding assuredly, “And yes, I know exactly how those feel on you right now. Trust me, I wouldn’t give you two a punishment I hadn’t experienced myself~”

That remark caused Pinkie and Marble to stare at each other worriedly. Neither of them were sure what all Limestone had done in diapers herself, but they certainly didn’t want to ask either. Instead, all they could do was look back at the poofy garments hugging both of their rumps so tightly. Pinkie was the first to try and move one of her legs, and shuddered when she heard the loud crinkling of the plastic and padding against her crotch. Marble could barely move, but she could hear the faint crinkling from her own diaper when she shivered a little.

“Alright, let’s get you babies downstairs!” Limestone led the way as she trotted past the two padded mares, and went down to the first floor. “I already have a little ‘lunch’ set up for the both of you. Heh heh~”

Pinkie and Marble winced at how cheekily Limestone said that. As soon as she was out of sight, Pinkie got in close to whisper into her sister’s ear, “Okay, no matter what happens, we can NOT give her the satisfaction. Whatever you do, just… just keep it in, okay?!”

“Kee… Keep it in?!” Marble’s eyes darted around whie whimpering under her breath. “Nnnffff… I… I don’t think I can do it, Pinkie…”

“You rather want her to watch you wet yourself?!” That idea made both of them shudder uncomfortably. Pinkie seemed especially unnerved as she shook her head. “No. W-We can’t let that happen! Let’s just try our best to… I dunno… w-wait it out or something…”

Marble sighed and nodded in agreement to Pinkie’s plan. Unfortunately, as the two tried their best to slowly waddle down the stairs, each stretch of their legs reminded both of them of how badly they needed to go. The last thing either of them wanted to do was endure such a humiliating punishment under Limestone’s orders; but alas, neither of them were sure how long their resistance could last…

“Oh, girrrrrllllssss… Come on doooowwwwnnn~”

Pinkie and Marble were groaning badly by the time they reached the bottom of the stairs. They weren’t sure which was more discomforting: the growing pressure both of them felt in their bladders, or the obviously vindictive tone in Limestone’s sing-song voice. This may have been a “punishment” for the two of them, but it was clear that their sister was enjoying it just a little too much. If their parents were still here, they would’ve waddled right over to them in an attempt to stop Limestone’s debauchery from going any further; but alas, the two diapered mares were left alone to face her incoming wrath.

They were blushing hard when they finally waddled their way into the kitchen, with their diapers loudly crinkling with every step to alert Limestone of their presence. The mare was already standing with a cocky grin, while an old high-chair was pulled out of storage to serve as the girls’ new seating. Marble Pie blushed worriedly at seeing the vintage chair already placed at the table. Meanwhile, Pinkie Pie just stared at Limestone flatly. “... seriously?”

“Seriously~” Limestone gave the chair a playful pat with her hoof while staring the two down. “Apparently, Mom and Dad gave the other high-chairs to the neighbors after their grandchildren were born. But since we still have this one, I’ll let you decide who gets a seat first~”

Pinkie and Marble stared back at one another with matching looks of silent dread. Marble softly shook her head, not wanting to try and sit in that tiny seat while her rump was so thickly padded. Pinkie didn’t appear to be too thrilled about the concept either; however, the last thing she wanted to do was subject her sister to a fate caused by her own actions. Since she was the one to get both of them napping in the first place, Pinkie closed her eyes with a sigh before turning back to Limestone. “Ughhhh… I… I guess I’ll do it…”

“Perfect!” Limestone grinned devilishly while lifting up the serving tray latched above the seat. Pinkie waddled over to her, with the crinkling of her padding causing Limestone to snicker a little. Pinkie was looking increasingly miffed the closer she got to her, but she managed to keep herself from saying anything in that moment. Instead, Pinkie was helped up onto the high-chair with Limestone’s help. “Nnnghhh… Here you go, you big baby~”

Marble Pie could only watch from the kitchen doorway, with her legs inching themselves in closer to keep her padding tightly nestled against her crotch. It wasn’t nearly enough to keep the pressure at bay, but it was the best chance she had at keeping herself dry. Her eyes glanced over at the bathroom door, which was within view across the kitchen behind Limestone and the high-chair. She had no idea how she could get her way over there, or even if she could get past the lock and sneak inside. However, Marble had to struggle not to widen her eyes when she took notice of the metal key hanging by a chain right beside the doorway.

“Mmmphhh!!” Pinkie clutched her muzzle tightly with a muffled groan, while her padded backside was stuffed into the tiny confines of the chair. As she sat with her torso lurched forward, she could feel her bladder being pressed down against the padding over her crotch. Limestone didn’t hesitate to snap the serving tray back down over Pinkie’s lap, which pressed the diaper even harder into place. Pinkie whimpered and tried to cross her hind-legs together while they dangled off the floor; but alas, Limestone was quick to take notice and shake her head.

“Uhh, uhh, uhhhhhhh~” Limestone’s devious grin widened when she reached for something she was hiding underneath the table: a large bundle of rope. “Now, Pinkie… We both know I’m not gonna let you off that easy~”

Before Pinkie could try to kick her away, Limestone grabbed her flailing hooves with ease and placed them against the high-chair’s legs. Marble’s jaw dropped at how effortlessly her sister was able to keep Pinkie in place, even as the mare struggled and yelped against her grasp. Limestone’s work on the farm provided her with more than enough dexterity, as she got both of Pinkie’s hind-legs pried apart and tied against the chair’s front legs. Pinkie’s head lurched down with a heavy groan, while her padded crotch was on full display with her legs spread wide-apart.

“And since you wanna be a fidgety baby…” Limestone used more of her rope to bind Pinkie to the chair, all while Marble Pie stared in absolute shock. Pinkie whimpered worriedly, but she soon found her torso tightly pressed against the back of her high-chair to keep herself from bucking out of her restraints. By the time Limestone got to work tying Pinkie’s forelegs to the chair’s armrests, Pinkie winced at how securely that rope-work proved to be. If she wasn’t so worried about the growing pressure of her bladder, she would’ve pointed out how Limestone’s rope-work was as good as Applejack’s. Nonetheless, she was too embarrassed to say much by the time she found herself completely tied up and unable to move an inch. “There!” Limestone stepped back to admire the finished product of her hoofwork. “Heh~ Now all we gotta do is wait…”

Pinkie’s head lurched up to stare at her in shock. Both she and Marble quickly realized that there wasn’t anything on the kitchen table, meaning that Limestone’s “lunch” claim was most likely just a ruse. Granted, neither of them felt particularly “hungry” after filling themselves up with milk and taking a nap. But at the same time, the diapered mares tensed up with worry when they realized how determined their sister was to make them fulfill their punishment.

“Nnnghhh!!” Pinkie tried to move against her restraints, but it was obviously to no avail. Not only were her limbs all tied down to the chair to render her immobile, but the additional rope around her stomach meant that she couldn’t try lurching forward in her seat. Even if she did manage to move in the high-chair, Limestone was standing right in front of her to make sure there was no funny-business; plus, there was a good chance that Pinkie would just tip over and fall onto her face. She eventually closed her eyes to avoid staring at her sister’s insistent smirk. “L… L-Limestone, please! I ca… I c-can’t do it like this…”

“Oh, you can’t?~” That dire plea got Limestone to grow an especially wicked smile. She trotted away from Pinkie in the high-chair, which left Marble to look over and see how restrained her sister was. Her blush intensified when she saw how notably Pinkie’s white padding was displayed in the chair, practically staring back at her like the eyes in a creepy painting.

Meanwhile, Limestone cleared her throat to get both her sisters’ attention, just as she stood beside the kitchen sink. “Maybe this will help both of you… relax~”

With that, Limestone turned one of the faucet knobe the tiniest bit, which made a small trickle of water pour from the spout. The moment that thin stream hit the metal sink and began to pour down the drain, Pinkie and Marble groaned through their teeth at the same time. “MMMGHHH!!!~”

Limestone chuckled with a look of pure amusement, and leaned against the kitchen counter to watch her sisters squirm. Marble tried her best to keep her legs tightly closed, but her diaper was too thick to get her rear hooves to even touch together. Meanwhile, Pinkie was writhing in her high-chair while tightly restrained, and unable to even try to get in a more comfortable position. The sound of trickling water made her swollen bladder feel downright painful, and caused her breathing to grow more rapid between those harsh groans. Marble tried not to whimper too audibly herself, and hoped that her silence would be enough to keep Limestone from glancing over at her for too long.

“Oh, is there a problem, Pinkie Pie?~” Limestone walked up to her sister’s high-chair, and placed a hoof atop one of her thighs. Pinkie struggled to keep her muzzle clenched shut, but her sister could still hear her whimpering when she got in close. “Oh, look at how badly you’re blushing,” she said with a mocking jeer. “Is that because you need to go wee-wee like a widdle baby… or is that just because you’re too embarrassed to let yourself do it?~”

“HMPH!!” Pinkie tried to hang her head away from Limestone’s taunting grin. Even though she felt like her bladder was about to burst, she couldn’t deny that her sister wasn’t wrong about her humiliation locking her impulses in place. Even if she was being forced to do it, she really, REALLY didn’t want to wet herself like a little kid in some makeshift “accident.” Unfortunately, unless Limestone suddenly grew a conscience and decided to break her free, Pinkie was growing increasingly wary about how long she could stay like this.

“Well, don’t you worry about me…” Limestone kept a teasing grin as she got in front of Pinkie’s chair, and stood upright to rest her elbows against the serving tray. She brought one of her hooves down to press up against Pinkie’s padded crotch, which caused her to let out a strained moan from the building pressure. Limestone’s ears perked up from that peculiar noise, but she kept her smile unchanged in wait. “I got allllllll day to wait for you. Just like how you waited all afternoon for me to finish YOUR chores~”

Pinkie wanted to yell at her for keeping this punishment going, but she was too tensed up from the intensifying pressure to try opening her muzzle. Limestone gently rubbed at the smooth, currently clean padding that was being shown so prominently in Pinkie’s high-chair. Meanwhile, Limestone kept a direct stare on her sister’s deepening blush, and the pained grimace she had as she struggled to hold it in. Due to how sternly she was keeping her eyes on Pinkie, Marble tried her best to silently waddle around the table and out of Limestone’s line of sight. After a few long, strenuous minutes of hearing Pinkie’s groans and the sink’s trickling water, Marble was able to “sneak” past the two as covertly as she could in her crinkly diaper.

Unfortunately, as soon as she made a waddling crawl past them, she didn’t seem to notice Limestone shooting her a knowing glance with a light smirk. “Hmph~”

The faucet kept running the tiniest bit, trickling more water and causing Pinkie’s legs to strain against the ropes. Her lips were pursed so tightly together, only the faintest whimper could be heard when Limestone loomed in closer. Tears were starting to bead at the corners of Pinkie’s eyes, both from the physical and mental strains that kept her from letting loose. She tried her best to focus on her breathing, but it merely came out in feeble pants through her flaring nostrils. Marble was trembling just as badly behind her sisters, but her shaky hooves held her upright just long enough to reach up and grab that metal key…

“Come on, Pinkie…” She pressed her hoof even tighter against that diapered crotch, which made Pinkie’s muzzle finally reopen so she could groan out loudly. “If you want to be let out of this chair, I expect you to do it~”

She couldn’t pull her body forward while her torso was tied to the chair, nor could she close up her legs in any way. She tried to grit her teeth in anticipation, but it did nothing to counteract the additional pressure Limestone was giving to her bladder. Marble winced from how badly Pinkie was sounding in her bondage; but with her own bladder swelling up painfully in need of release, she tried to use her sister’s struggling as an advantage as she carefully inserted the key in the bathroom lock.

“Oh, Marblllleeeeee~”

Marble Pie froze up in horror, just as she got the door unlocked with that damn key. When she turned around slowly, her eyes as wide as a character anticipating a monster in a horror movie, she was met with the sight of Limestone staring at her with a haughty grin. She pulled away from Pinkie’s blushing face, only to turn the high-chair around so the two padded mares were facing one another. Marble may have been able to unlock the door, but she was frozen in peril when she saw her sister squirming badly in her bondage.

“I know you thought you could avoid seeing it happen, but trust me…” Limestone reached towards the sink right beside herself and Pinkie, and turned the knob so the trickling water could be a full-blown pour. Even more water loudly hit the bottom of the sink, which locked up both of the sisters’ knees and made them groan loudly. All the while, Limestone narrowed her eyes on Marble as she lifted up the high-chair’s serving tray. “... even if you try to enter that bathroom, this is going to happen to you~”

“MmmmmmMMMNNNNGHHHH!!!~”

Pinkie Pie couldn’t take it anymore. Her eyes were clenched tightly shut, and her muzzle was contorted badly enough to show how shameful and mortified she felt in that moment. Her hind-legs quivered tightly against the ropes, but they remained spread apart so her sister could see all of her padded crotch. Marble Pie’s muzzle went agape, but nothing could come out to cover the sound of that distinctly loud hiss:

‘Psssssssshhhhhhhhhhh…’

“AaaaaaAAAAAaaaaahhhhh…” Pinkie hung her head, but her blushing expression was clearly seen by both her sisters as she finally relieved herself. She looked both humiliated and relieved at the same time, while the crotch of her diaper instantly began to swell out from the gushing flow that hit the padding. The white plastic ballooned out slowly between her legs, before a faint yellowish hue started to seep through the padding and into view. Pinkie’s heavy sigh lingered on for well over a minute, but the hissing from her diaper continued for much longer while Limestone watched with glee.

“Ooh, somepony had to go~” Limestone leaned in to get a good look, and snickered at the sight of Pinkie’s diaper expanding out between her thighs. The pink mare was trembling with a faint whimper, but she couldn’t stop pissing herself until every drop was soaked into the padding. What was formerly a smooth white surface behind the transparent plastic, was now pressing tightly against the outer restraints while bloated out and a deep shade of yellow. Pinkie shuddered with a tight cringe on her face, since she was able to smell the acrid scent of her urine clear as day through her diaper. Limestone didn’t seem to mind the smell, and merely huffed before giving her crotch a playful pat. “Therrrrrre you go. That wasn’t so bad, was it?~”

If Pinkie wasn’t so embarrassed by what she just did, she would’ve shot her a deathly glare for asking such a thing. Unfortunately, since Pinkie wasn’t able to hold her bladder, there was nothing to keep Marble Pie out of Limestone’s focus for now. Her heavy blush disappeared to reveal a petrified pale, not that it deterred Limestone’s grin by any means.

“So, how about you?~” Limestone gave the high-chair a couple pats with her hoof, before tilting her head at her still-clean sister. “You think you can hold out longer tha--HEY!!!”

Before she could finish, Limestone tried to lunge in when Marble suddenly threw open the bathroom door. She may have had a disadvantage in speed with her added gait, but she was close enough to the door to rush in without warning. She slammed the door into Limestone’s face, and locked it shut before she could try to burst in. By that point, Marble was moaning out weakly as she waddled over to the toilet and tugged at her padding.

“H-HUH?!” Marble expected the diaper to be easy enough to rip off her waist, even for somepony as frail as herself. But as soon as she pulled at the elastic cuffs of the plastic pants, she was horrified to discover that they were as tightly wrapped as the packaging that ironically held scissors. Her panting grew more rapid and fearful, and she spun around a couple times like a dog trying to chase its tail. But as soon as she saw the back of her pants’ waistline, her pupils shrunk to the size of pin-pricks.

She recalled hearing a click when Limestone got her and Pinkie into the plastic pants; however, she would’ve never realized that was from a small padlock that was tightly secured around the base of her tail. She began to hyperventilate as she helplessly pulled at her shorts, but alas, the plastic proved to be far too much for the lone diapered mare to handle.

“Oh, Marble…” With that jeering voice causing her sister to shiver in dread, she wasn’t met with any opposition when she used her personal key to unlock the door from the outside. Marble could only stand with a mortified look when she saw Limestone’s cocky grin at the open doorway. She could also hear Pinkie Pie groaning out in the kitchen, but it was doubtful she could do much at that moment. Marble Pie could only breathe out shakily, before her eyes drifted down to see a new item being held in Limestone’s hoof.

“Since you wanna try being a naughty filly…”

Limestone grinned rather eagerly, and held up a shiny metal bar with hoof-cuffs at both ends.

“... now the two of you will have to keep those diapers on until you used them both ways~”