As the end of the day bell rang at Françoise Dupont High School, Most students were eager to leave and go to whatever after school social lives they had. Most, but not all. 
For one Marinette Dupain-Cheng, School was preferred to what awaited her after classes where let out. The teenaged girl/Superhero had been having a few..ok A LOT of accidents lately and her parents while trying to be understanding about it had gotten fed up once she went from not just wetting herself off and on to having a full blown 'uh-oh' accident in the seat of her panties. 
She couldn't even explain what was going on, As it wasn't the result of a super villain or anything like that and a trip to the doctors had reported her in clear health.  it was said doctor's belief and her parent's echoed it that it was just laziness on Marinette's part and she was faking they were accidents.
As such, if she wanted to act like a naughty toddler who refused to potty train she'd be treated like it, and she had been enrolled at a after school daycare that specialized in potty training.  Furthermore her panties had been replaced with a mix of princess pull-ups and thick over night diapers, her parents making it clear they expected a solid week of no tinkles or uh-oh's in her undies if she wanted big girl panties back. 
All of this was enough of a nightmare, going to school in pull-ups and trying to keep them hidden, but it only got worse as it turned out Chloe of all people worked at the daycare Marinette had been enrolled in.
the blond self proclaimed princess of Paris was totally delighted to find out Marinette was in the potty training program and made slight 'changes' to the rules regarding her training.  
For one while Marinette was suppose to be in pull-ups during the day, Chloe made sure the second her little 'bug butt' as she nicknamed Marinette (Ironically she didn't know Marinette was lady bug, it was more in reference to the size and shape Marinette's bottom took when the bulky diaper was on) was thickly diapered and 'somehow' always seemed to be too busy to sit Marinette on the potty and when the inevitable happened would just cite the wet or messy diaper as proof that Marinette was just a silly big baby.
Since she was SO kind and dotting on Marinette when other adults were around and even when in private her words would say one think but her tone anther, Marinette couldn't prove she was being set up to fail. 
Worse, when she tried to use the example that her pull-ups were mostly dry when she got to daycare in her parents minds that only proved she was using them by choice, only soiling herself when others would have to clean her. 
So, when the final bell rung Marinette toyed with the idea of just running off and avoiding daycare as she gathered up her books and packed her book bag.
She was making a B-line to the side exit from the school when Chloe's voice rang out in the hall.
"And just where do you think YOUR going?" She asked. 
Marinette turned around and gulped as Chloe made her way over, a frown on her perfect face as she for in front of Marinette and folded her arms. "Well little girl?"
The other students in the halls knew the tone Chloe was using and not eager to have her anger spill over, quickly left leaving it just the caretaker and the diaper girl in the halls.
"I was um.. Just heading..to daycare?" Marinette stammered out, a weak smile plastered on her face.
"Mhmm.. you know the most direct route is out the front entrance Little lady." Chloe said.
"O-Oh but it's..such a nice day out, I wanted to..enjoy..the outdoors and take the scenic route!" Marinette said, scrambling for a excuse.
"...You know you ARE right. it IS so nice out today." Chloe said and gave a smile that would of made Hawk moth flinch."In fact it's so nice I think you can play outside today, after we get you in your diapies." 
the mental image of being outside in a t-shirt and her massive diaper, sitting in a sandbox as people walked by and laughed flashed in Marinette's mind and she turned crimson. 
"N-no! please!" She yelped and then she did something else, a loud hiss heard in the empty hallway as she flooded her pull-up in fear.
Sadly it was already damp from a scare during chem lab where they had been a loud BANG and the inner thighs of her red pants started to turn dark red.
"Awww, Poor little Marinette sprung a widdle leak huh?" Chloe coo'ed, and patted the whimpering brunettes head. "it's ok, I won't make you play outside. come with auntie Chloe and we'll get you all cleaned up and safe and snug in your diapie bug butt."
with the stains growing and knowing she had no choice in the matter, a defeated Marinette just nodded her head and let 'auntie' lead her to daycare.

Thankfully for Marinette her wet pants were noticed thanks to a careful placement of a note book, at least till she got to the daycare where Chloe tugged the notebook away and whistled for the attention of all the other kids.
with the oldest kid after Marinette being five, giggles and chuckles broke out among the little guys and girls. 
"Look everyone! Poor Marinette made her pull-up leak, who thinks she needs to give up on them and just wear her diapies alll the time? show of hands!" Chloe coo'ed.
out of the other 26 kids in the room, 18 hands shot up (the other 8 were too young to understand.) 
"I..it's just..I didn't.." Marinette started to whined and whimper, tears building up in her eyes. 
"Awww, it's okay." A little 4 year old girl said, coming up and hugging her leg. "Potty training is hard, but when ya finally get it you'll get big girl panties like me!" 
the little girl moves to lift up her dress to show her Disney princess panties off but Chloe quickly stopped her. 
"See Marinette? Goals!" Chloe said and smirked as she took hold of Marinette's hand and lead her towards the dreaded changing table.
"You don't have to enjoy this QUITE so much." Marinette grumbled, her bottom lip sticking out as she was still trying to fight back tears. 
"Now now bug butt, be nice. I can always send a note home with you telling your parents how you tinkled in your pants in front of me on purpose~" Chloe said in a low evil voice, a warm smile on her face so any of the other workers would think that she was giving words of encouragement to the pants wetting teenager, pausing the pat the top of the changing table as she took the back pack away for the poor girl.
"You wouldn't!" Marinette gasped then groaned as she climbed up on the changing table, hands covering her face as her shoes were removed and Chloe started to undo the wet pants. "..Oh who am I kidding, you totally would."
"I'm glad we got that bit of nonsense out of the way. But I'll make you a deal bug butt. if you act like a happy little baby girl for me today, no fits, no huffing and NO attempts made at using the potty.. I'll keep your little leak allll to myself." Chloe offered as she tugged the pants off and tossed them in a hamper to be washed asap. 
"..why would you want that? Do you LIKE wiping my poopie butt or something?" Marinette asked. 
it wasn't a insult but more of a genuine question, and Chloe could tell and smirked. 
"hey, you get your rocks off crapping and pissing yourself, don't judge me if I like reducing my rival for Adrien's affection to a big baby girl. besides whats your only other choice? end up coming to school tomorrow in one of your thick diapies? Personally I would find that hilarious but i doubt you will." Chloe said as she ripped the sides of the destroyed pull-up and tossed it into the diaper pail.
Marinette pictured it, there was NO way any of her pants would cover her diaper's, and one good breeze is all it would take to flash off her huggies in any of her dresses. Or even worse, if her Parents went total punishment mode and made her wear one of her short skirts, with the diaper peeking out!
shuddering from the mental image and the cold wipes being used to clean her up Marinette mewed softly and looked to the side. 
"H-How..how do I act like a good little girl for you?" she asked in a low, defeated voice.
"you can start by calling me auntie." Chloe said, a smug look of victory on her face.

when Chloe had first been forced to come and work at the daycare as punishment for trying to drive her parents car, she had been convinced this was going to be the worst month of her life. 
Thankfully the fates smiled down on her and gave her a way to amuse herself as she served her time in the front of nerdy Marinette being dropped off by her parents. 
Learning the whole story it was just simply too delicious not to take advantage of and she toyed with maybe extending her time at the daycare as her punishment was due to end in a few days or offer a more 'one on one' effort to 'help' little Marinette conquer the potty.
Either way it was food for thought at a later point as she took out not just one of the stupid thick diapers the day care carried for older kids (to be fair, the diapers were thick then normal for any age range as the owner hated the thought of kids leaking on the plush carpet) but two of them, making use of a razor blade to slice slits in the first diaper. it was a trick she had been shown the first day as a way to deal with the super soakers and she thought it would be just perfect for a excuse to have her little nerd bug butt waddling more then usual. 
the poor little nerd didn't even dare argue and actually to Chloe's delight, started to suck on her thumb as she watched. technically she could of let Marinette keep sucking on her thumb but there was always a better solution aka more humiliating. Setting the diapers down with the slit's cut in it and putting the razor in the locked compartment where it was kept in the table, Chloe tugged Marinette's thumb out of her mouth with one hand and reached into anther compartment and pulled out a cleaned and sterilized pacifier with the other.
"no no no little Bug butt. No sucking on your thumb. little girl's hands are covered in germs. here, suck on this instead." Chloe coo'ed, ironically though she wouldn't know it, popping a paci in Marinette's mouth that had a red and black ladybug theme on the mouth guard.
Marinette whined and looked ready to spit it out for a second, then a look of defeat washed over her again and she suckled loudly on her paci. 
"That's a good girl!" Chloe coo'ed and tickled Marinette's chin, making the teenaged baby giggle and smile behind her paci.
with the big babies mouth full, it was time to finish getting that butt back in diapers, and with expert ease that comes from doing a task over and over again Marinette was powdered and double diapered. 

'I think i would rather face powered up versions of every akuma villain I've ever taken down this put up with this.' Marinette grumbled, sucking loudly on the paci in her mouth as Chloe finished putting her diapers on. 
"ok bug butt, time to go play, need help getting down?" Chloe asked, voice dripping with honey and clearly loving every second of this.
'laugh it up..next time your in danger I'm letting the akuma victim of the week torment you for a bit.' Marinette thought, sitting up with a bit of difficultly. 
scooting on her butt and nothing she couldn't even get close to bring her knee's together she went to slide off of the changing table and land on her feet as usual, however the bulk and the difference in balance had other ideas.
She did land on her feet, for all of 3 seconds before her legs wobbled and she plopped down on her diapered butt, pacifier dropping out of her mouth as she let out a yelp more out of shock then any pain due to the ample cushioning her backside had.
"oh dear! Did baby fall and go boom?" Chloe asked, bring her hands together and putting them to the side of her face. "You poor little helpless thing~ Are you alright? do you need auntie to kiss your boo boo better?"
"I..Uh.." Marinette stammered and squirmed, then it clicked. 
Chloe might of just said that last part to torment her, but since Marinette had just fallen on her BUTT.. 
"Y-yesh aunite Chloe. widdle Marinette fell on her bum bum and needs a kissy better!" Marinette said in a loud voice, getting attention from the whole room. 
the look on Chloe's face said it all, she hadn't been expecting to have to follow up and with the whole room watching now the pressure was on.
Rolling over onto her hands and knees, Marinette stuck her padded rear out and wiggled it. 
"A-auntie, a-aren't you gonna kiss it b-better wike you pwomised?" Marinette asked, putting a sad babyish tone to her voice that would make Chloe look like the meanest person ever if she didn't follow though.
Face turning crimson and gritting her teeth, Marinette tried not to giggle as Chloe replied. 
"O-Of course I'll kiss it better sweetie. I made the offer after all." She said, then kissed her index and right fingers on her left hand and pressed them to the back of Marinette's diapered butt. "that better?" she asked. 
"Noooo! you hafa us your lips or it doesn't work auntie!" Marinette 'whined' and wiggled her massive padded rump. "D-Don't you want it ta git better?"
"O-Of course I do," Chloe said, and slowly got down onto her knees, thinking of just how much she was gonna make this little bitch pay for this. "Auntie Chloe cares about all the little guys and girls under her care." She added, trying to stall for time. 
'of all the days to wear lipstick.' she thought with a mental groan then closing her eyes and puckering her lips leaned in. 
Marinette was waiting for the and as 'auntie' leaned in she pushed back and smushed her pampered bottom on Chloe's fart, while pushing with everything she had and letting out a muffled fart.
Sure there was gonna be hell to pay, but the memory of making Chloe kiss her ass and eat a fart was going to be Marinette's new favorite memory for a long, long time. 

The end...for now