[Mental Regression, ABDL, Diaper Use, (Hyper) Soiling]

"Alright, Akagi. What did you do this time?"

The air was ever slightly tense within the Admiral's office as he peered straight ahead at the black-haired fox he called a Carrier. His gaze was the tiniest bit stern, but it was more exhausted and done with the girl's antics than anything else.

"Oh? Why, I've done nothing that you wouldn't want me to, dear Admiral. After all, getting rid of obstacles that'll get in the way of our fight against the Sirens is a good thing, isn't it?" The vulpine Akagi chimed, smiling ever seductively as she leaned across the table. "Besides, I know you quite well, dear Admiral. You've been hanging out with girls that have your worst intentions in mind, unlike your beloved secretary. I've done you a great favor, can't you see?"

The white-clad young man narrowed his eyes as he rested his head on the backs of his hands. "True. On some level, you might be correct. Your fellow ship girls do draw my eyes away due to their erotic bodies and their kind smiles... much like your own, lest you forget." His words continued to carry that tired sense, as he leaned back in his chair for a brief moment. "Perhaps it really was the best for me that you dealt with them in such a swift manner..."

The red-tailed fox grinned with the sleeve of her kimono-like uniform hiding the malicious edge to her expression, only for her eyes to briefly widen as she heard a mysterious clicking sound. "W-Wait... My Admiral? What are you doing?" A tinge of worry ran down her spine, which disappeared moments later...

Alongside the rest of her conscious mind, as she quietly fell to the floor. Already, a sign of what she was becoming was readily apparent due to the slight trail of drool running out of the corner of her mouth.

"Unfortunately, this just means I'll have to tend to you with all of my love and care. And if you knew me as well as you said you did, then you would've realized that this was the only way forward. Sleep tight, Akagi. You'll be much more agreeable by the time you wake up."

---

"Addy! Akagi's mwessy!"

Days later, after the Admiral had carried out the necessary retrofitting to his Secretary ship, both of them would hardly if ever be seen in public around the Naval Base. and for a good reason, given what he had done to the fox that had caused so much trouble amongst his fleet.

The young man clad in white smiled as he reached his hand onto his secretary ship's head, slowly running his fingers through her hair as he ruffled it. "That's a good little girl. Akagi. You know how much I like it when you've filled your nappies."

His words were a lot less tired now, filled with an appreciation for the girl that tried to keep him all for herself. In a way, she had actually succeeded given how little he showed himself around the base anymore. But when you had a baby as big as her on your hands, who would blame you for sticking around and making sure she was happy and content at all times?

Big was awfully accurate too. The fox Carrier, formerly carrying a dignified air that concealed her cutthroat nature as a yandere had been neutered in many different aspects. Sure, she still had a bombshell of a body that was nearly on display due to the change in attire, but she didn't know how to use it properly, nor if she really should care that she looked like a big girl at a first glance.

No, her knockers and her hips did little to conceal the truth of the matter hanging between her legs. Reaching down to her ankles was a single, solitary and deeply browned diaper that threatened to sag even further as the seconds passed by. This was her 'diapy', as she had started calling it. The only thing that could contain the extraordinarily huge amount of waste that she now produced on an hourly basis. Just as 'Addy' wanted it.

"Ehehehe... Addy's pwasing Akagi..." The drooling baby lost her footing as her infantilized mind started to wander, causing her to plop her butt straight down and into the mess below. She immediately started giggling as the brown bulge mushed around her bottom, conforming around the shape of her derriere as she started rocking back and forth gleefully.

The light in her eyes faded briefly as she started pulling her foot upward, her babified instincts taking control as she gently stuffed the toes on her feet into her mouth. She didn't have a pacifier, so she made do with what she had whenever she felt the need to satiate her infantile oral fixation. Something that earned another little bit of petting from the 'older' Admiral as he gently rubbed her back.

He smiled for a moment as he mockingly waved his hand in front of his face. "I have to admit, I could go without how much stink you make. It makes it hard to breathe in the office... but you wouldn't be my little baby fox if you didn't make poopies this huge and pungent." The lad chimed as he hugged his toe-sucking baby girl, who giggled in response to the affectionate gesture. She couldn't really do anything else!

"Adda..." Akagi muttered as the drool on her foot slowly ran down her leg, pooling on her dirty diaper as she continued to just absentmindedly lick and suck on those cute little beans she called her toes. It was all a part of her instinct at this point. Why shouldn't she be playing with her feet when they were good toys, right there in front of her?

The Admiral gently ran his hand through her hair once again as he put a hand further down below. "Hmmm... Can you make a bigger mess for me, Akagi?" He asked, and the fox nodded in response, preparing to clench so that she could fulfill her Admiral's command... only for him to kiss her to stop her.

"Nono, not now, baby girl. First, I want you in a new diaper. One that you can mess to your heart's content. I want you to make sure you fill out the entire office, from one wall to the next. Then you'll make 'Adda' super proud. Don't you want to do that?" He continued, and the light in Akagi's eyes returned as she popped the foot out of her mouth.

"Uhuh! Wanna mwake Addy bwig pwoud!" The eager fox chimed as she rocked back and forth on her messy seat, only to jerk so far back that she ended up plummeting onto her back harmlessly. She didn't really notice, but her Admiral had baby-proofed the entire office to ensure that she couldn't hurt herself in any way, whether she consciously wanted to or not. Just as a precaution. A precaution that definitely helped in this case.

His smile filled his face as he kneeled down, kissing the fox-eared girl on her cheek once more, causing her to giggle childishly. "I didn't even have to tell you to lay down, and you did it all on your own. You're such a good baby girl, Akagi." He praised her again, and he could practically feel the warmth radiating off her happily blushing cheeks as he looked to the big brown diaper, rolling up his sleeves slightly...

Here came the hard part.

First, he had to get it all off. It wasn't nearly as simple as it sounded, given the overall size of that thick thing in comparison to the rest of the girl's body. He had to be extremely careful when he peeled back the tapes, just to ensure that he didn't end up making a proper mess of things once they were all undone. He kept one hand firmly on the front-end of the waistband as he peeled back the last tape, before grabbing the back-end the second the last tape was removed, to ensure that they stayed mostly together and that none of that mess spilled out...

A few beads of sweat dripped down his brow as he gradually pulled it off the baby girl's bottom, tying a knot using the waistband before pushing that massive diaper over into a corner of the room. A corner that had been gradually filled up with similar disposable diapers that he hadn't quite had the chance to get rid of yet. Pretty hard to do so when you primarily stayed in your office all day dealing with your little baby. "Gonna have to see if I can't convince that greedy little kitten to make a garbage chute or something, just to deal with all of these... Maybe a base-wide pail..."

As the young Admiral continued to mutter to himself, he turned back towards the fox-girl laying on the padded floor and her thoroughly browned bottom. A natural result of rocking back and forth in her own poopy, yet not at all one that he minded for long. He had the supplies to deal with it.

"Here Akagi, lay your belly down on this little blankie, and I'll deal with your dirty bumbum." He motioned towards a clean white blanket, and seconds later the fox had done as he asked, squirming a little as she laid on the surface with her stomach facing the ground.

Next, came the ordeal of wiping her clean. Instead of just using wet wipes like a person who hadn't expected an industrial-sized bunch of waste from a ship girl, he used a proper cloth to get it all off. First, he dunked the cloth in a nice little bucket of soapy water, then he started rubbing the poor gal's bottom all over. From one cheek, into the crack, and out onto the next. Every time the surface of the cloth got a little too brown, he wrung it up over the bucket and went back to work.

After a few repetitions, that butt was spotless! Not a single bit of her cute figure had any trace of her own mess left on it, only the soap and watery sheen that was left behind on her completely cleaned buttocks. The Admiral could only smile as he moved the bucket full of water away, leaving him to deal with the shitty slurry later. He didn't need to think about it for longer than necessary.

"Okay then, flip onto your back again, Akagi. It's time for your new diapy."

The fox lit up as she quickly flipped onto her back and started reaching out towards the diaper that her 'Addy' held up above her head. "Diapy! Diapy!" She cried out happily, eyes fixated on the pamper as it was gradually pulled out of her reach, and in turn, her squirming intensified. What a giddy little girl...

To properly slip the diaper onto his little angel's bottom, the Admiral had to raise her legs up with one arm before sliding the butt of the diaper underneath her own cleaned cheeks. Once that was done, he pried open said legs with both hands to spread them apart, letting the middle section of the padding spring up as it weaved into that gap. Once that was done, he only had to hold down the front against her crotch to properly secure it, while he used his other hand to tape it shut.

With that, he was left with one properly padded fox girl, his very own secretary ship snugly secured and unable to make a mess in his office.

Outside of the messes that he encouraged her to make, of course. "Stand up, Akagi. It's time for you to let loose. Make super-huge poopies for Addy, okay?"

"Okay! Bwig Pwoopies!" The foxy baby shouted as she jumped onto her feet, and immediately her expression started to strain. She tried to push and push and push, but nothing came out to start. She had a lot of pressure inside her, that much was clear from how hard it was to actually push anything out.

But then her stomach started to groan. Then a few toots of gas spewed out of her bottom. Her expression relaxed as she didn't need to push anymore, as the signature sound started echoing throughout the room. The sound of something serpentine snaking its way into that crinkly compartment in the back of her diaper.

"Akagi pwoopy..." She muttered, confirming her condition as she slowly squatted down. In seconds, the diaper meant for regular adults started bloating outward. Second, by second, it filled further with inches of solid waste that just made her undies spread further and further. What had previously snugly clung to her thighs was gradually being pushed outward, resulting in the diaper reaching down to her knees while the back of it sagged...

But that was hardly the end. She needed to push more! She needed to make big messing for her admiral! He wanted her to make them bigger, so she snapped out of her brief haze as her expression grew more concentrated in a childish fashion. She needed to push! Push! PUSH!

The slow growth that had caused her diaper to reach her ankles at this point suddenly exploded. What was previously a rate of a few inches per minute turned into a few feet every few seconds, and then some! Bit by bit, the size of her diaper multiplied repeatedly. One moment it was filled with so much poopy that it was as big as her, and the next the endless stream of shit had caused it to be twice as big as her, and still growing!

The diaper soon reached the ceiling as the little foxy continued to push and push, not letting up until she knew that she was stuck. Even though the floor and the ceiling pincered the diaper, it took nary a few more moments before it just continued to grow. It didn't visibly change in height, but the way both the top and bottom caused the floor and ceiling to groan was more than enough proof that it was still growing.

Her expression started to relax again as the poopies had nowhere left to go. While they had caused the integrity of the office to be shaken as it couldn't grow further upward or downward, the sides had continued to expand outward until they hit the wall. Now the groaning continued, rattling at least 80% of the room and risking that the room itself would break... and at that very moment, the flow stopped.

"Pwooooopy... bwiiiiiig..." The soiled little sister muttered as drool slowly ran down her chin once more, the light had faded from her eyes as she started running on instinct again. She tried to briefly prop her foot into her mouth once more, only for the Admiral to lend her a hand by pushing it upward so that those toes could rest inside of those lips until the 'real' Akagi would return.

Of course, he was smiling at this point. Proud of what she had done. "You did so well, Akagi. Addy's proud." He chuckled, looking back at his desk worriedly for a moment. The rest of the base was definitely going to notice her at this point, and then he'd have a few different powerful girls trying to skin him for daring to tamper with one of their own, even if she had previously caused them problems...

Then, a devious thought slipped into his depraved mind. The same mind that loved every second of taking care of that big baby. "...Why don't I just make them all my big babies?" The thought grew and grew as his smile turned into an equally delighted grin. He had work to do, work that involved contacting Akashi and studying the big messy fox occupying most of his office. After all, he wanted his entire fleet to mimic her, so he needed to ensure that he understood every aspect of her.

His fleet would never be the same after he enacted his plan.