After a summer of being trapped in the RV around Ben and gramps, who while she loved and had enjoyed saving the world with, Gwen Tennyson was excited to be back home. Not just because she had missed her parents, or that she was excited for the start of the school year, But also because she had a interesting way of relaxing and indulging herself and it was one that hadn't been a option in the closed off confines of the rust bucket.
Left to her own devices so to speak after having spent hours talking with her parents and playing a few board games, Gwen was almost shaking with delight as she wiggled out of her pants and then her undies, bending down and tugging out her secret delight from it's hiding spot under her bed: A package of extra thick white and pink diapers, called little stinkers. 
Because you see, Gwen a true blue, chin drooling goo goo gaga diaper girl who could waste away hours in her huggies and crapping herself. 
Of course while she delighted in the feeling of the diapers, and doubly so when wet and triple so when stinky.. She was also smart enough how life ruining it could be for her if her pervy little squishy diaper fun time got out and took great care to keep it a secret, even taking medications to tone down the smell of her BM's.
'Yeah, doubt I'd be getting looked at by all these private schools and the like if they knew I relax by going all durrr and pooping myself.' Gwen thought with a blush, 
She had opened the package now and was taking one out, wondering not for the first time just what was it about diapers she liked so much, but like always the need to be a big dumb diaper baby for a few hours ended the mental debate and soon she was sprinkling baby powder on and getting ready for a afternoon of padded fun. 

Ben was already missing hero life, since Grandpa Max had made it clear he wasn't going to be able to get away with going hero as much as he had during the summer AND when you add in he'd gotten in for for 'somehow' forgetting he'd been suppose to do book reports and the like to help make up his grades (Technically He shouldn't of passed but his parents had come up with the extra school work over the summer deal)
"You would think what with keeping Ghostfreak from turning everyone into monsters I would get a bye on having to a read stupid book but nooooo.." Ben grumbled, kicking a rock on his way over to Gwen's house.
the only way he was going to get all of the backlogged work done was going to be with Gwen's help, his parents and Gwen's knew it and while they didn't know what Gwen was doing, her parents who had come over for a visit had told Ben they were sure she'd be glad to help him.
'yeah, after she makes fun of me. we both know she'll wanna lord over how much smarter she is being a little miss perfect.' Ben thought and huffed as he let himself into his aunt and uncles house, having been given the spare key.
Little did Ben know he was about to find out that Gwen wasn't so perfect after all though he'd never have a chance to tell anyone and be believed. 

It wasn't long after Gwen had gotten her diapie on that she felt the need to go, since she never knew exactly for sure how long she would have the house to herself before diapering up she would always 'pre-game' so to speak and take laxatives so that she could be a mush tush baby in short order. 
She had already wet herself, giggling as she posed in front of her mirror and pointing a finger at herself so the reflection pointed back.
"You, are a big dumb diaper wetting toddler! Now let's make it even better!" she giggled and turned around, looking over her shoulder so she could watch and she dropped into a semi squat.
bearing down and grunting, it wouldn't take more then a loud brassy fart or two before her efforts were rewarded and a large lump started to form in the back of her diaper, growing and making the room fill with the soft crackle as her mostly silently movement expanded the diaper. 
"Mppph~ fuck yeah.. Poop that diaper you big dumb-" Gwen was groaning, then her door opened up and Ben was standing there smirking.
"BABY!" he finished, smirking and then laughing and pointing. "Oh my god, little miss perfect is a pamper packer!"
"B-Ben! Get out!" Gwen yelled, trying to stop herself but atlas, her bowels weren't finished and she frozen in place as she proved what a super duper diaper pooper she was, more lumps filling out the diaper and making it discolor and sag. 
If it wasn't for the fact that Ben was watching her crap herself Gwen would of been proud of the load she was making, but somehow being watched robbed her sense of joy.  go figure.
"Oh wow, Look at that! you're really doing a number on your huggies huh BABY Gwen?" Ben snickered, coming over and then slapping a hand on her mush tush, making Gwen screw up her face and cry out. 
No stranger to mushing her stinky butt or bouncing in her load, she was taken back by how kinda NICE it felt to get her stinky rump spanked by someone else.
'Ok, file that away for anther time.. have to ignore that for now and-' Gwen was thinking when Ben swatted her butt for a second time. 
Her eyes rolled back and she got a goofy smile on her face, biting her lower lip as she trembled, and failed to keep a low moan of delight back.
"..are..you..Oh man! this just get better and better! stinky baby Gwen wikes having her smelly diapies spanked!" Ben roared with laughter, swatting away at her behind now as she finished up. "I can't wait to tell everyone about this! oh, I should get pictures! OH!! I know I'll just have you do all my homework from now on and in return I'll swat your shit swelled diap-" Ben was saying when suddenly a pink energy field surrounded him and held him up in the air.
a flustered and shaking Gwen turned around, her ruined diaper plastered to her ass but she gave a weak but evil smile.
"Yeah about that.." She said, willing her composure back.
"...Is it too late to say I can pretend this never happened?" Ben asked with a squeak.
"WAY too late."

Ben found himself with think to think and reflect on his actions as he was pinned to a wall by Gwen's magic, the back of his undies having been pulled up and tugged over his head so he could suffer a painful wedgie and his mouth stuffed with a pair of her socks (Clean thankfully) while Gwen went and cleaned up.
He was positioned in stuck a way that using the omimatrix was out of the question and as he heard the shower running all he could do was hope that Gwen would calm down and they could just have a good laugh about this. 
Or hey, maybe she would take him up on the offer to tease and spank her for homework, it could happened!
'yeah, and I could grow a second head and start a career doing duets with myself. but best possible endgame is she just erases my memory.' Ben thought, squirming and ironically feeling his own bladder filling up from fear. 'Oh yeah, that'll be great..you already pissed her off, let's make a puddle on her carpet and see how much that helps' he thought to himself sarcastically.
The shower turned off and as Gwen made her way back, Ben could only hope and pray that maybe she would just live and let live. 

All cleaned up though annoyed her diaper butt time had been drastically reduced because of Ben, Gwen had gone over several punishments/ways of keeping him from blurting out her fetish. most of them involved some over the top violence which she knew would be a HUGE no no, she couldn't just cripple or kill Ben, that wold be wrong. 
'I guess I could just erase the memory from him or..Or..' and Gwen smiled to herself as she came in, smirking at the restrained Ben.
"Having fun wedgie boy?" she asked, and listened to his muffled attempts to talk. "Oh really? well seems like a pity to let you down now.. but I will..well after I take care of our little issue." Gwen said, coming over and having her spell book out. 
Ben whimpered and thrashed about, clearly scared. 
"Relax doofus, I'm not going to hurt anything but your pride, and in the process maybe help you become a better student and hero." Gwen said cheerfully, her statement making Ben pause and look at her in confusion. 
"I'm going to turn you back into a toddler, and remove the omiatrix from you and claim it for myself. everyone will just remember that there was a series of female aliens who saved the day. You'll still be you though with a bad case of baby babble and well, who's going to believe a widdle 2 and a half year old when he goes on about how I'm a diaper girl..or that he's a big boy who turns into aliens? It'll just sound like you were watching TV and wanted to be like the heroes you saw on them." Gwen said and smiled, stroking Ben's cheek as he started to struggle and cry. "Hey hey..it's not going to be all bad Ben...I'm going to make it so you'll enjoy your stinky diapers just as much as I do, after all I'm not a monster. Just a witch." Gwen said and then pulled the socks out of Ben's mouth. "Any last worlds before I return you to huggies and sleeping in a crib?"
"GWEN PLEASE I'M SORRY!! I WON'T TELL ANYONE PLEASE DON'T DO THIS!!" Ben cried out, crying and hysterical and wetting himself, making Gwen step back. 
"I should be mad at you for the puddle..butttt considering what I'm about to do, I think that makes us even." She said and then there was a flash of pink light.

Ben sat up, looking around and his vision was all distorted for a second. rubbing his eyes and tossing a blanket off of himself he realized he must of blacked out and been put to Bed, Gwen had clearly just been trying to scare him. 
Or at least that's what he thought till he pulled his fists away from his eyes and noted how TINY there were, that his watch was gone, and that he was in a power ranger themed pull up that was bloated with pee. 
Looking around his room he was growing more and more horrified as he found himself not only in  crib, but his room had been turned into a little boys nursery!
Slowly getting to his feet and knowing his baby fat, Ben wobbled over to crib bars, the mattress too soft and making walking a challenge but Ben had already made up his mind, he was NOT going to fucking crawl!
Shaking the bars (As if that would help) he called out, yelling for his Mom, or his dad..or really anyone, wincing at how babyish his voice sounded and whining as he couldn't get the words to come out right.. basically able to cry for 'mama' or 'dada' and getting out the name 'Gwen' and words 'diaper' and 'pooper'...everything else was just gibberish.
even as he stood there, ranting away a weird sensation started to take hold of Ben, and he trailed off confused as to what he was feeling even as he squatted down and his butt started to feel warm, it wouldn't be till the smell hit his nose that he would clue in, yelling out even as the door to his new nursery opened up and his mom was coming in.
"POOPIE! BEN POOPIE!" he cried out, howling and farting, tears welling up in his eyes even as a shudder went though him, the smell aside, this was starting to feel kinda nice.
"Whew! I'll say you are! I guess that settles the debate over trying to potty train you yet, that was your last pull-up." His mom said, waving a hand and laughing going and opening a window.
"I buh daba ba guh Gwen nwa me poopie!" Ben whined, trying to explain to his mother what had happened but of course all he got was a patronizing grin from her and she came over, patting his head and then the back of his pull-up as it was drooping big time from the weight of his load.
"Uh huh..really? amazing!" she giggled and then pulled him up. "I was gonna wait for you to finish but I don't think that pull-up has much life left in it, and you don't wanna make a stinky mess all over your bed right?" she asked, cooing and then making silly faces. 
Despite himself Ben giggled and clapped, shaking his head no.

One humiliating trip over the training potty and then a change into a thick massive diaper, and Ben was carried downstairs trying to hide himself in his mother's shoulder/chest, embarrassed that he was in just a diaper since it was nice and warm in the house.
It would of been bad enough being seen by his dad like this, though he was convinced that just like mom he would also think Ben hadn't grown up yet, It was the OTHER voices he had heard as he was being brought down that had made him all shy. 
Uncle Frank's loud booming voice, then teasing voice of Aunt Natalie and the worse of all: Gwen's voice!
"So guess who was right and who was wrong about Ben being ready to potty train?" Ben's mom asked as came into view of the living room where everyone was. 
"Hmm well since Ben's in a diaper..and squirming..I'm gonna say..You!" His dad said, smirking and wagging his eyebrows playfully. 
The comment was enough to make little Ben giggle despite himself, pulling away from his moms shirt to flash a smile.
"..heh, your not man enough to try and put this butt back in diapers." His mom said, setting Ben down on his feet and giving his butt a pat. "Go play with Gwen! he was saying your name over and over in the nursery." 
"Was he now?" Gwen said, scooting her butt off the couch and holding her arms open, a big smile on her face that undoublty looked warm and friendly to the adults..but to little Ben it looked like a crocodile inviting it's prey in.
He shook his head no and babbled away again, tugging on his mom's pant leg and pointing at Gwen, getting her name out every so often, as everyone chuckled.
"Yes Ben, that's your cousin Gwen. I know. Go play." Mom said, giving his rump anther pat. 
Letting out a big huff, Ben's eyes suddenly lit up as he scanned the room and saw some coloring books and crayons. Sure he couldn't talk right, but he could totally write out a message!
toddling over as fast as his little legs would let him, a effort not helped by the bulky diaper and more then once he almost fell over, Ben made his way over and yanked out the coloring book and the crayons, flashing Gwen a big toothy smile. 
One that she returned with a slight smirk. 
"Oh, do you wanna make me a pretty picture Benny? You KNOW I love your art!" Gushed Gwen. 
'ok..she's not worried worried..what does she know that I don't.' Ben thought then looked down at the cover of the book. 
it had some generic super heroes on it, fighting likewise a generic villain but what worried Ben was he couldn't make out the words on the cover.
Opening the book up Ben plopped on his butt, flipping though the pages and seeing that he couldn't read ANY of the text in the book, it looked like just gibberish to him and also..man did he apparently stink at staying in the lines. whining and slamming the book shut Ben tossed the crayons towards Gwen and was huffing and sniffling, on the voice of a toddler tantrum. 
"Whoa hey little man! we do NOT throw things!" His dad said, going to get up. 
"I'm sorry, I don't know what's got him all worked up!" His mom added.
"hey it's ok, I bet I know what he wants, but he's upset about it because he failed potty training." Gwen said, smiling and getting up and scooting over to Ben on her hands and knees then plopping herself down close, snatching him up and into her lap. "Somebody wants his favorite cousin to give him a ba-ba of milk doesn't he?" She coo'ed and tickled his chin. 
despite that being the last thing int he world Ben wanted right now, his babyish instincts kicked in and he was gurgling and cooing, laughing and nodding his head yes. 

It was a ironic hell for Gwen of all people as she rocked the little guy in her arms. she had meant to make Ben just helpless and unable to blab her secret,.. but now as she saw the freedom he had to waddle around in diapers with them on display, and him being expected to use them, well she felt jealous.
'Look at that massive diaper! I just wanted him babied! I didn't know Uncle Carl and Aunt Sandra went mega diapers!' Gwen mentally huffed, playing with Ben while waiting on aunt Sandra to make the ba-ba of warm milk. 
she was tracing a finger on his tummy and clearly Ben had been a SUPER ticklish toddler from the way he was giggling and squirming, even though every so often he was able to hit her with a look of anger, it was clear he was all there. 
'Well if he gets to wear a big old diaper and poop himself whenever he wants, I'm gonna help out! I can live the dream though him!' Gwen thought and only Ben would notice the light pinkish glow as Gwen traced a few symbols onto his tummy, the adults for the most part had gone back to ignoring them. 
Ben went to go and cry out, to get help somehow (not that he would of been able to) but it was too late anyways as aunt Sandra was back and handed Gwen the bottle of warm milk, the last thing needed to trigger the little spell she had just placed on lil Ben. 
"Bottoms up!" She coo'ed and popped the nipple in his mouth and smiled as his nurse urge overrode his common sense and he started to suckle.

Ben knew that nothing good could come of the spell on his tummy tum, but he was just helpless to do anything about it. thinking about it the worst that Gwen could really do with everyone in the room was making him crap himself and well, he wasn't the best at reading people but he had a feeling that Gwen was actually jelly of his diaper butt status. 
the idea amused him and as the warm milk dulled his already less then brilliant mind he came up with a ultimate revenge plan: he was gonna take all the big smelly diaper poops she wished she could and rub it in her face (Figuratively not literately.)
Suckling down the milk as fast as he could and feeling the urge to go building up(only because it was being magically induced, from now on it would be clear he'd have no control over it till he potty trained, if he'd even be able to) Ben pushed the bottle out of his mouth when it was have drained and whined, baby babble and Gwen's name. 
"Gwen, he needs to be burped." Aunt Natalie said.
"oh, ok!" Gwen said and lifted him up, getting his head over a shoulder and patting his back.
it actually felt really nice and Ben was quickly losing his hate for this new form if he could get this kind of attention, but he still had a revenge plan to enact and had to do it at least once. 
Letting out a massive belch that got comments of 'nice one!' from the men in the room, he pushed back again Gwen with all the power in his tiny arms till he could lock eyes with her, then pulled back in so he could give her cheek a drooly smooch even as all hell broke loose in the seat of his diapers. 
"Wow, as much as he went earlier and he still has more in him!?" his mom chuckled. "I'll take him from you Gwen."
"N-No that's ok." Gwen said, blushing now and he could feel her hand on his mush tush. "Clearly he wants me right now, right Ben?" 
Ben giggled and nodded, puffing out his cheeks as he helped the poopie escape out into his diaper and made a load that comparatively, put Gwen's to shame.

In the aftermath Ben and Gwen semi patched things up, she couldn't undo the spell so Ben WAS stuck like that but she did manage to make it so she could understand him at least and earned the title of his number one favorite babysitter. 
Of course if  either of their parents had know such babysitting session was filled with both of them diapered and drinking from baby bottles and having poop off's, they would of come to a end, or at least had a babysitter for both of them, like that nice Julie girl who had moved in down the block.. 

The end?