Luna gagged as the last dollop of lima bean foal food found its way into her mouth. Hot tears ran down her face, the result of eating so much vile mush for so long.

Around her, Nightmare had allowed the ponies of town to gather in a large crowd. Well, less allowed and more ordered. Everypony had been forced to clump together for the best view possible as Luna was spoonfed another round of foal food. She at least took solace in the fact that Nightmare hadn’t forced her into a highchair again. Maybe it was simply because it was easier for Ponyville to see her shame this way.

Speaking of, Luna shifted in her messy diaper, the mush now much colder, but still just as slimy. Every time the poop squished and slithered across Luna’s backside, she was reminded of the dirty deed she’d done. The fact that Nightmare still hadn’t changed her was only adding to her feelings of shame, to say nothing about the town's worth of ponies staring her down.

She could still hear fleeting snippets of conversation from them. Though she couldn’t make out much, it was pretty clear there was only one thing they could be talking about: their pathetic foal of a Princess.

Twilight Sparkle was down in front, her friends to the right and left of her. Nightmare had insisted they had to get the best view, but Luna partially believed she didn’t want to let them out of her sight. She still didn’t know what Nightmare knew about the Elements of Harmony and their inactivity. If she expected Twilight and company to go for them at any point, she may end up killing them to spare herself the trouble.

Just the thought made Luna shiver, but she didn’t know if it would be any better to reveal the Elements had been returned to the Tree or not.

Nightmare finally pulled the spoon from Luna’s mouth, letting the lima bean flavored garbage rest on her tongue. The feeling made Luna shudder, and she hastily swallowed, despite how badly she wanted to throw up.

“Such a good eater,” Nightmare commented with a smile. She undid Luna’s bib and levitated it towards her mouth. Nightmare found a clean corner, and dabbed it against her tongue before using it to wipe off Luna’s mouth. “There we go!”

As the bib floated away and dissipated into fog, Luna couldn’t help but blush with indignation. How could Nightmare slip so easily between mother and vicious dictator?

The remnants of her lunch stuck around in her mouth. Luna whined as the nasty mush clung to the roof of her mouth and the insides of her cheeks. She squirmed in discomfort, but only succeeded in spreading the mess on her rear.

Nightmare sat down on the grass and crossed her hind legs. She looked over to Luna and patted her lap, telling Luna to join her.

At first, Luna hesitated. Right away she knew Nightmare wasn’t forcing her onto her lap simply because it would look like Luna was willing to the citizens of Ponyville otherwise. If she did so without putting up a fight, it would look like she was going along with this like an obedient foal would.

But if she didn’t, Nightmare could very easily make her. And the punishment that could result would be devastating.

Her sore rear ached at the memories of the spankings. Even with the diaper’s padding and her own poop, it still hurt to sit down.

Just then, the fog in front of Nightmare’s gather together and formed a large, full foal bottle.

Luna immediately perked up, her mind instantly going back to earlier that day. Her vile breakfast had been washed away by the sweet taste of milk.

She started to get up, needing no more beckoning to join Nightmare. Before she could stand however, Nightmare shot her a glare. Luna retracted, fearing she’d done something wrong. As she lowered herself back to the ground, Nightmare nodded, and it was then that Luna realized she was supposed to crawl.

Even though she didn’t want to demean herself further, what would it matter at this point? Besides, she wanted to get the rancid aftertaste of the foal food out of her mouth.

Moving down to her fetlocks, she crawled over to Nightmare, ignoring the looks she got from the crowd.

She climbed onto Nightmare and rolled over, wincing as her messy diaper squished against Nightmare’s lap. Though it was subtle, she thought she felt Nightmare shudder a little bit at the feeling of the cold, dirty diaper. But she could’ve just imagined it too.

Nightmare took a moment to smooth out Luna’s skirt, delaying her bottle. Luna whined in anticipation, the gross taste coating her mouth becoming too much to bear.

“Now now, hush, sweetie.” Nightmare wrapped a hoof around Luna’s head and pressed her into the dark fluff of her chest. “Do you want your baba now?”

“Yes,” Luna said, voice cracking from shame.

“Yes what?” Nightmare’s eyebrow rose.

Luna gulped. “Y-Yes, Mommy.”

“Good girl.” Nightmare picked up the bottle, and brought it to Luna’s mouth. She eagerly parted her lips, ready to receive the amber nipple and start suckling.

“Princess Luna, what gives?!” A shout rang out from the crowd. The bottle stopped just in front of Luna’s face, and she whined. Looking up, she saw Nightmare’s face darkling staring down the interloper, so Luna turned to look to.

Rainbow Dash had stepped forward, shaking with anger. “This is… just a trick right? Or something? You gonna stomp Nightmare’s flank into the ground any second now, right?”

Luna frowned, not knowing what to say. Would Nightmare punish her if she responded? Would she not get her bottle?

Just then, the fog at Rainbow’s hooves leapt upwards. It latched around her face, forming a pacifier in her mouth and binding it with a strap around her head.

The shock on Rainbow’s face was so great that it looked like her eyeballs might pop free.

“Hmmphf?” She said. Instinct cause her to reach up with her hooves to try and remove the foreign object, but that proved to be a mistake. With her hooves chained together, moving them independently was impossible. She slipped and fell to the ground, muffled screams chasing after her.

Ponies all around her backed up in fright, though the closest--Fluttershy and Applejack--immediately moved to help her up.

Luna faced Nightmare again, ears folding down in fear. Luckily, Nightmare’s dark face was back to feigning cheer. “Now then.” She shoved the bottle into Luna’s lips.

“Mmf!” Luna said in surprise. That quickly faded, in favor of wrapping her lips around the nipple and suckling.

Warm, sweet milk splashed into her mouth. The gross leftovers from her breakfast were dispelled, and once again Luna was left with the happy sensation of suckling and the wonderful reward it yielded.

Drinking from her bottle was so euphoric, that Luna even forgot about the massive mess in her diaper. For a moment.

She didn’t even mind when Nightmare’s hoof found her ponytail and started innocently twirling it. Luna just buried her cheek into the comfy chest fur and let her eyes go half-lidded.

She ignored the crowd’s stares and murmurs, and the muffled screams of Rainbow Dash. Right now, her baba was all that was important. It was the one good thing she had in what was quickly becoming an ocean of terribleness.

Then, the bottle was suddenly pulled away from her mouth. Luna whimpered as drops of milk hit her lips. She saw that the bottle still had half of the formula still in it, and desperately turned to Nightmare, demanding an explanation.

The bottle merely faded away, as Nightmare had her attention on the sky. Luna was confused for a moment, but when she followed Nightmare’s line of sight, her relaxed state evaporated.

Not far away, she could see Celestia’s chariot descend

Her face paled, and Luna’s heart started beating faster. Her sister was here!

Relief and concern flooded her. Celestia had finally found them, which meant they might all be saved! ...Might.

Nightmare’s power, along with the fog that basically controlled this town, was a dangerous threat. Not to mention the last time Celestia had defeated Nightmare, she’d needed the Elements of Harmony. This time, that wasn’t an option. And she had the handicap of an entire town being hostages.

Luna squirmed, hating how she was squashing her own hopes for freedom.

The chariot descended behind the crowd of ponies, how by now had all turned to witness the arrival of the Princess, some even cheering.

Luna felt herself rolling over suddenly, until her belly was on Nightmare’s lap. The fog right below her climbed up to her mouth and formed a pacifier between her lips. Despite her surprise, she knew better than to try and spit it out.

Nightmare patted her head gingerly, which made Luna worried. Her captor didn’t seem all that concerned that the cavalry had arrived. In fact, she seemed pretty calm.

The crowd was parting now, some ponies applauding as Celestia approached.

Luna suddenly panicked, realizing her sister was about to see her in the most compromising situation she’d ever been in. She tried flinging herself free of Nightmare’s lap, but magic kept her in one place pretty easily.

That didn’t stop Luna from whimpering though. And squirming. She did everything she could to push against Nightmare’s power, not caring about the consequences. No matter what, she couldn’t let her sister see her so… beaten.

“Oh, calm down, Lulu.” Nightmare suddenly pressed her hoof deep into Luna’s dirty diaper.

The dolled up alicorn froze, before a long, slow shiver ran through her body. The poop in her diaper shifted and squished noisily, spreading all over her backside.

And then Nightmare started rubbing. Slowly and deliberately, up and down. Luna’s faced flushed, burned, and exploded with redness. She kicked her hind legs in protest and whimpered, but that didn’t stop the rubbing.

Finally, Princess Celestia broke through the crowd. She was flanked on both sides by only a few guards. She must’ve come hoping to end this quickly, and as such hadn’t brought an entire army with her.

That was a mistake.

Celestia herself wasn’t paying much attention to Nightmare, another mistake. Instead, she seemed more focus on soothing the citizens. Though Luna couldn’t quite make out what she was saying, she could tell her sister was talking to the denizens of Ponyville, offering assurance and compassion.

Either she was overconfident, or blissfully unaware to the danger presented.

Luna was just glad she hadn’t been seen yet, even if the inevitable was only being delayed. She still tried in vain to wiggle away, but Nightmare only seemed to press deeper as she rubbed the butt of Luna’s dirty diaper.

The overwhelming stench of her own mess made Luna’s eyes water, but part of that could probably be attributed to shame. Even if her sister didn’t see her soon, she would surely smell her. Either way, the last sliver of Luna’s dignity wouldn’t survive for long.

As if on cue, Celestia turned to them, her warm face transforming into an angry glare. “Nightmare Moon, you have--” She crashed to a stop, finally noticing her sister.

Luna whimpered, squeezing her eyes shut. Even so, the image of her sister’s face was burned into her retinas.

Her widened eyes juxtaposed by shrunken pupils, her dropped jaw that had been on it’s way to hit the ground, her nose crinkling at the nasty stench of Luna’s diaper, and the twitch that plagued both her eyelids and her ears.

What made matters worse was that Nightmare refused to stop fondling her dirty diaper. If it already hadn’t been blatantly obvious Luna had been dominated into submission, the slow, deliberate rubs against her mushy butt only made it clearer.

“L-Luna, what happened? Why are you… how… what?!”

Luna squeezed her eyes shut, wishing her mane wasn’t tied back in ponytails so she could hide her face behind it. After a few seconds of wishing she didn’t exist, Luna felt a hoof pat her head and she tentatively turned to look at Nightmare Moon.

“Come now, Luna. Why don’t you answer your big sis?” Nightmare grinned mischievously. “Tell her all about why you’re in diapers."

Luna sniffled. “I no wanna,” she whispered through her pacifier.

Nightmare’s hoof suddenly slammed deeper into Luna’s diaper, causing the poor mare to shiver and ‘eep’ with surprise. Nightmare calmly but her mouth to Luna’s ear and coldly hissed, “I won’t ask again.”

Biting down on her pacifier, Luna nodded slowly, sniffling. She turned to face Celestia’s aghast expression as a new wave of humiliation crashed over her.

“I…” Luna sniffled, barely fighting back any more sobs. “I hadda ac’ident, so Mommy put me in diapees.”

Her face muscles contracted in a painful wince the second the sentence left her mouth. The fact that she had said that would’ve been humiliating enough on its own, but what piled wasn’t even the town, or her sister bearing witness to it, it was that it came out so easily. It was like Luna really was the baby she was forced to pretend to be.

Celestia’s face compressed with worry, as well as a little disgust. Her nose wrinkled at the scent of Luna’s dirty diaper, but even more noticeable was the look she wore. It was clear that Luna’s answer had only raised about a hundred more questions.

Princess Celestia shifted her attention to Nightmare Moon, her expression. “I don’t know what you’ve done to my sister--”

“I diapered her, of course,” Nightmare interrupted. “Poor filly needed it too, if her mushy tushy didn’t already give that away.” She patted Luna’s dirty rear, eliciting another sniffle from the dolled up alicorn.

For just a moment, Celestia was taken aback, but shook her head and dug her hooves into the dirt. “You have no right to do this to the ponies of Equestria. Eternal night, enslavement, ...t-that…” Luna’s ears dropped. ‘That’ was pretty obviously meant to refer to her treatment, which was humiliating enough already.

Behind Celestia, the fog began gathering. It was pretty unnoticeable, but Luna had been dealing with the fog for quite some time and recognized it immediately. Nightmare was about to attack.

“Cel--” Nightmare suddenly snapped Luna’s mouth shut with magic. Her lips clamped over the pacifier, as the dark forces controlling her body forced her to suckle innocently without so much as a muffled cry.

“Nightmare, I’ll be sure you pay for this!” Celestia yelled.

“Hmmph,” Nightmare said, thoroughly unimpressed. “Seems like you’re a tad cranky. How’s about I get you ready for naptime?”

Celestia’s resolve shattered into confusion with a single look. “Uh… naptime?”

Luna kicked and struggled, but it was too late. The fog shot out from the ground as five distinct tendrils. Four wrapped around the guards, so fast they didn’t even have time to react. Celestia managed to turn around and gasp before her tendril engulfed her.

“MMMMMPH!” Luna screamed, still unable to stop suckling. She watched as her sister and the guards struggled in their foggy prisons, their silhouettes difficult to make out.

The townsponies looked on in horror as their savior was blanketed with fog. Nightmare just cackled with delight.

Then, Luna felt herself being picked up. Before she could even react, Nightmare sat her--butt first--against the ground. Luna squeamishly shivered as her mess explored yet untouched areas of her diaper.

Feeling a tug at her neck, Luna looked to see her leash being pulled down. The fog at the ground formed a steel peg, embedded into the dirt. Nightmare swiftly wrapped the leash around it, ensuring Luna had nowhere to go for now.

Then she stood up.

At that instant, the tendrils of fog encasing the ponies before them vanished. All four guards dropped to the ground. Their armor had been stripped away, replaced now with chains. All of their limbs were wrapped in binds. Thick iron bands were clasped over their necks, with chains connecting to the ground. Their mouths all bore thick, uncomfortable looking muzzles.

Some looked around in panic, some screamed, but none could do anything.

And Princess Celestia had it the worse out of them all.

Her wings and horn were bound, that much had been a given. Her mouth now bore a massive purple pacifier, and given how forced downward her jaw appeared, the bulb must’ve been gigantic. Straps from the pacifier wrapped around Celestia’s head, as well as over and under her snout, locking it down so she couldn’t speak. Her legs had escaped chains, but only for a far worse fate.

A stockade had been erected around her, keeping her neck and forelegs firmly in place. Her hind legs hadn’t fared much better, as a spreader bar kept them pushed far apart.

From Luna’s angle she could also see Nightmare had taken the liberty to diaper Celestia. A massively poofy pale purple diaper encased Celestia’s hindquarters. Pink ruffles ran down the butt of the garment, showing off just how dainty and foalish it was. And it showed that off right to the entire crowd of Ponyville.

“There we go,” Nightmare said with an evil gleam in her eye. “Almost ready for naptime.”

“Mmm?” Celestia tried to look around, but couldn’t escape the stockade to see properly. She did manage to lock eyes with Luna, who quickly turned her attention to the ground out of shame.

I should’ve tried harder to warn her. Luna thought. The realization that her last hope had been subdued slowly started to sink it. Luna almost didn’t want to accept it.

Celestia struggled against her new prison, wiggling her diapered rump to the tune of a crinkly chorus. Nightmare laughed.

“Now, now, isn’t somepony just full of energy?” Nightmare clicked her tongue disappointedly. “I guess I’ll have to tire you out before you can go beddy-bye.”

“Hmmph?” Celestia’s brow furrowed. Luna’s did too; she didn’t like the sound of that.

With magic, Nightmare lifted Celestia’s tail high into the air, ensuring her diapered plot was exposed for the captured and broken-hearted townsponies to see.

“I’ll know you’re all tuckered out when you can’t hold back your bowels anymore,” Nightmare said. “So I guess I just won’t be able to stop until your diaper is all full.”

“Sterp whurt?” Celestia struggled to ask.

Luna’s stomach sank. She knew where this was going.

Nightmare outstretched a hoof, and fog leapt up to accommodate her. Soon, a long, wooden paddle had formed in Nightmare’s grasp, and she grinned wickedly.

She raised the paddle into the air. Ponies gasped. Twilight cried out with a desperate, “please stop". The bound guards shook their heads, screaming behind their muzzles.

Nightmare shot Luna a brief glance, and winked, making the degraded alicorn shiver. Then the paddle came down.

CRACK!

It moved like lightning, but sounded like a clap of thunder. The paddle traced an easy path to Princess plot, delivering a vicious spank that snapped the wood in half.

Celestia screamed, her pacifier choking most of the sound. Luna tensed up, biting down on the bulb of her own.

She had never been on the receiving end of a spank that bad. Even with a thick, plushy diaper to cushion the impact, that had to have hurt.

Luna winced hard enough to make her cross her hind legs, and then just winced again as cold poop pushed to her inner thighs and beyond.

Nightmare brought back the paddle, letting fog reform the end. She casually glanced down at Celestia rear and shook her head. “No poopie yet? I guess I have to spank you some more then.”

A teary-eyed Celestia quickly recovered and tried to look over at Nightmare as she shook her head. “Nuh! Nu! Mmm mmm!”

Nightmare raised the paddle high, delighting in the situation. It was clear that, while humiliating Luna had been fun, breaking Celestia was what gave this evil mare life.

CRACK!

The end of the paddle snapped off again, and fell to the ground.

Celestia wailed, tears already streaming down her face. Townsponies were looking away now, covering their ears as best the could and slamming their eyes shut.

The paddle reformed, and rose once more.

CRACK!

Another clap of painful, painful thunder. Luna’s own rear stung just from the memory of receiving her spanks. She couldn’t imagine what Celestia’s plot must’ve been feeling just then.

CRACK!

Luna slammed her eyes shut as she heard her sister’s muffled sobs. It was too much to bear. One more and she might--

CRACK!

“Stop it!” Luna screamed. She burst onto all fours, ready to charge Nightmare. But not half a step in and her leash caught her, sending her face plummeting into the ground.

Luna bit down, grateful her teeth found the pacifier instead of her tongue. Her snout stung after hitting the dirt. She tried to sit back up to nurse it, but found the fog had grabbed onto her face and wouldn’t let her move.

Then she heard Nightmare’s slow, deliberate steps move towards her. Right up until her forelegs blocked Luna’s vision

“Lulu,” Nightmare said with all the anger of a scorned mother. Her magic let the paddle rest in Luna’s line of sight for a moment before letting it whish around to her backside.

CRACK! SQUISH~

The wind from the swing was strong enough to ruffle Luna’s skirt and brush her pigtails forward.

The pain was enough to make lose consciousness for a half-second.

Tears immediately leapt to her face, clouding her vision even before she could focus properly again. Nightmare’s scowl suddenly dominated her face.

“Do you want me to spank you again?”

Luna whined, in so much pain that she couldn’t even form words.

“I didn’t think so.” Nightmare’s voice was smooth, but darker than a barren night sky. “If you don’t want anymore spankies, then you better do exactly as I say. Am I clear, sweetie?”

“Y-y-y-y-yes… M-m-m-m-m-mommy-y,” Luna sniveled, hot tears working their way down her face.

“Good. Now, I’m going to go back over to you sister, and I’m going to keep spanking her until she’s filled her diaper up enough for it to touch the ground,” Nightmare said, voice dripping with the pleasure she would experience from the act, and also the hate she felt towards Celestia. “While you sit here like a good filly. And every time I spank Celestia, I want you to burst out in the cutest, happiest, foalish giggles you can. Understand?”

Luna was mortified, but slowly nodded.

“And if I think, even for a moment, that those ditzy little laughs aren't genuine, I’ll give you the same treatment as her.” Nightmare nudged her head over to a whimpering, sobbing Celestia. “Ok?”

Luna nodded again, quicker this time.

“Let me hear you say it.”

Luna shuddered. “Ok, Mommy.”

“Good girl.” Nightmare stood up, and used her magic to set Luna back into a sit. The poor mare whimpered as her stinging rear mest the ground, the pain only slightly alleviated by cushy padding and cold mush.

Nightmare trotted back over to Celestia. She raised the paddle again, though her attention remained on Luna.

CRACK!!

It was the loudest--and no doubt most painful--spank yet. Enough to force a muffled scream from Celestia.

Luna hesitated for just a moment, but then forced herself to laugh. She giggled as joyfully as she could muster

Her sister looked up, and locked eyes with Luna once again. Her face radiated anguish and surprise, as though she’d been betrayed.

CRACK!

Luna laughed again, tears of sorrow rather than pain leaking from her eyes. She clapped her hooves, hoping the noise generated by her booties would cover up the few desperate sobs she couldn’t hold back.

CRACK!

It seemed whatever will Celestia had been retaining up till that point had finally been shattered. Maybe it was the pain, or the humiliation, or just seeing her own sister laugh at her, but nevertheless something broke.

Between her cries, she grunted, pushing hard. Her diaper bulged suddenly, and sank a little, now tinted ever so slightly brown.

Luna laughed as hard as she could, almost choking.

Nightmare grinned, and set the paddle down for a moment. She turned to address the onlookers of Ponyville. “I hope you all have a good view.” Her voice boomed. “I want everypony to see what their precious princesses have become. They’re little more than pathetic, bumbling foals, who would poop themselves just to escape a little bit of spanking.”

CRACK!!!

The paddle whipped down again, this time splintering into hundreds of pieces but fixing itself just as quickly. Luna winced, but giggled furiously anyway. No doubt the slimey, warm goop Celestia had just dropped into her diaper had be spattered all over her rear now. The way her sister’s face twisted in desperation only confirmed this.

“But I’m not done with either of them just yet!” Nightmare continued. “Not by a long shot. I’m going to pay back my millennium of humiliation twenty-fold. So keep watching, because it only gets better from here.”

CRACK!

Luna couldn’t laugh this time. She knew she would be punished for it, but there was just no way to keep going without devolving into tears. Nightmare had won. Luna had let her win and dragged down all of Equestria with her. There was no denying her cowardice in the matter; the role she’d played in being so passive, submissive, and downright foalish.

As much as it pained her to realize, she felt like she deserved Nightmare’s punishment now. She’d earned it for being so pathetic.

Though her crying, her bleary vision managed to catch a glimpse of Nightmare Moon. And she looked angry.

Luna whimpered, knowing the promised punishment was coming. It was going to be a long eternity.

Author's Note

Well, this is the end of this fic. (For real, this time.)

But, I'm not quite done with this story. It's been a blast to write, and I would immediately give it a follow-up if I didn't already have so much on my plate. So, hopefully, once I've gotten through a few more of my ideas, I can revisit this concept with a sequel.

Until then, thanks for reading!