With the benefit of hindsight Ben would of never of accepted Gwen's wager one bright and sunny Saturday morning, But instead when Gwen made the claim that she could kick Ben's butt in a best of 7 series in his new sumo slammer game, with the loser having to face public humiliation in just a diaper, he accepted without thinking. 
It had helped his choice that he'd just spent a summer of her tormenting him whenever she could over his need of bed time diapers, even locking him out of the rust bucket a few times and thus he was eager to see her bawling her eyes out in a diaper, but really he should of known something was up when she picked HIS game for the bet. 
He didn't though and while these thoughts ran though his head as she schooled him (dropping that she had actually been practicing for 7 hours a day to set up this little bet) he was a man of his word and soon found himself in a diapers and a light blue t-shirt that read 'number one nappy baby'
It wasn't even one of his pull up style bed time diapers either, Gwen had clearly decided to go all in and so as they made their way to the park Ben was waddling in the the thick white and green diaper that kept his knees from even getting close to touching, Gwen carrying a diaper bag over one shoulder and Ben having all sorts of bad feelings about how this was going to go down.
"Do..Do I even WANNA know why you picked such a thick diaper?" he asked as they walked (well waddled in his case.) 
"oh there are a few reasons, But while I explain them, you look a little thirsty.." Gwen said, smirking as kids playing in yards stopped and pointed to laugh and they got more then a few honks from cars. 
She pulled out a large baby bottle filled with a pinkish looking fluid and handed it to Ben who again, showed he wasn't one for thinking his action's though and took it and started to nurse on it.
"First of all, I picked these super thick diapers JUST for you because I want there to be ZERO doubt what you are, a big dumb nappy baby." She said with utter glee in her voice. "Secondly, I'm willing to alter the terms of the bet with you.. Instead of a whole hour at the park in your big puffy diapie." and she paused to pat his butt, making Ben whine around his ba-ba. "I'll go down to half a hour...IF you can keep the diapie clean. sounds fair right?"
Ben, who was chugging the actually very sweet tasting drink down like a glutton nodded, that did seem fair. no way he would use the diaper after all.
"Butttt~ if you make tinkles in your diapies, I'm adding 10 minutes. and if you go super dumb big baby, I'm tacking on 20. and finally, if widdle Benny destroyer's him's diapie sooo bad I need to change him, you're getting a hour tacked on." She cackled.
Ben pulled the ba-ba out of his mouth at that and shook his head, they were almost at the park now and wouldn't you know it, it was just full of kids today!
"W-what? No way!" Ben huffed.
"what, does widdle Benny not think he can keep him's diapies clean? are you THAT much of a baby you can't hold it for half a hour?" Gwen challenged. 
"I-I can hold it!" Ben huffed out.
"then why the huffiness? I think deep down you know you CAN'T hold it because your just a big stupid baby." Gwen said.
"I CAN HOLD IT! YOUR ON!" Ben yelled, and as Gwen smirked and they drew even more stares from the boys and girls on the park's playground, he couldn't help but feel maybe, just maybe he'd been played again.

While Gwen used a combination of magic and fast talking to smooth over Ben's attire with the adults who were supervising at the park's playground, Ben found himself the center of attention by the smaller boys and girls, all of them asking a bunch of questions and tossing in teasing barbs, and more then one hand patting his butt though when he';d turn around to tell them to stop it would just open his puffy rear for more butt pats.
"Are you like, special or something?"
"Why would you come out like this?"
"Ha! what a big dumb baby!"
"Aww! so cute!"
"ha! my little brother is 3 and even HE doesn't wear diapers anymore!"
"Please tell me you're not gonna stink this place up.."
"DO you wanna come play house with us?"
All this and more and Ben was blushing red as a cherry and found himself getting over whelmed, crying out for Gwen who came over and shoo'ed the kids off.
"heh, gonna be ok there nappy baby?" she asked, Patting his back to soothe him as far as he would be able to tell, but really activating the witches brew she'd tricked him into drinking. 
She wasn't skilled enough to just get him to load and soak his pampers all on her own, but the drink he had chugged down DID give her the needed access to make the magic happen and for bonus irony..the potion had to be drank willingly which Ben had done. Now she could load him up at anytime but decided that for maxim fun, she'd let him get close to getting out of the diapers before going to town on his bladder and bowels. 
There was a SMALL risk with the potion and spell combo she had picked for today's fun of ruining Ben's control and making him need diapers for the rest of his life but in her mind, that sounded like HIS problem, not hers.
"Y-yeah I'll be fine..can we um.. just go play or something?" Ben said, not knowing just how doomed he was, and just wanting to do something to make time fly by. 
"heh, of course~"

Picking the swing set Gwen was disappointed that Ben couldn't fit in the baby swing due to his massive diaper, making her a victim of her own success. Still it was semi fun getting the doofus on a swing and being the one to push him, if for no other reason then Ben quickly seemed to lose his big kid mindset and went al little guy, crying out 'higher! higher!' and giggling up a storm. 
Gwen kept a eye on the time which bit he in the ass as she had been kicking her watch when Ben had come back and taken a face full of diaper butt knocking her on her ass, and Ben just giggled like crazy.
'you think that's funny huh?!' she thought, dropping her plans to hold off on messing with his control and filling his bladder up to the brim. 'laugh off THIS!'
Ben went from laughing and teasing about hos Butt beats witch, like it was rock scissors paper then yelped and dragged his feet,trying to slow himself down on the swing as he had to take leak so bad he could almost swear his back teeth were floating!
"A-Ah! Nuh!" Ben cried out, his hands going to the front of his diaper, tiny spurts of tinkle escaping as he shook and fought a losing battle.
"Heh, what's wrong Ben? don't tell me your gonna use your diapie already! it's only been 9 minutes!" Gwen said, getting LOTS of attention. 
"I..I..H-How about a mulligan?" Ben asked, rocking back and forth and showing impressive control all things considered, though that just meant Gwen wanted his downfall to be even worse and with a slight gesture Ben's bowels would be as packed as if he'd gone to a all you can eat chilli fry place.
"Well I suppose so..I won't count the first wetting on you..as long as you don't go." Gwen started, and gave Ben's bowels a extra push. "Poopie." 
even as she said the word Ben's Bladder gave in, rapidly soaking the front of the diapers and making little storm clouds appear on the front of the white portion of the diaper, but any minor relief was off set by a thunder poot and then a sputtering fart and Ben's bowels decided to join the 'let's trash this diaper' party.
"A-Ah! No! I'm going poopie!" Ben cried out, getting roars of laughter from the crowd, though it turned to disgust as while the thick diapers were holding in the huge load firing out of Ben's poor hole, they couldn't hold in the stink. 
baseball sized lumps were puffing out the diaper and smiley faces with X's for eyes and tongue sticking out were appearing on the back of his diaper even as he semi rose a bit on the swing before the diaper sagged over the front and back of it.
"Geez Ben, I offer a deal and you take it as a chance to destroy your diaper? and what the hell did you eat!?" Gwen complained, holding her nose and groaning.  this was one part of her plan that she hadn't planned for and was reminding herself next time she did this to Ben to remove her sense of smell before hand.
"I-I can't stop going dookie!" Ben cried, and let out more thunderous and wet poot's. 
Viewers would argue and disagree on what happened next, but there were two main theories on it. One was that the weight and mass of his diaper mess caused Ben who might of been trying to get up to lose balance and trip and land face down in the sand around the swing set. the more juvenile (and ergo had more supporters) theory was the force of the last series of farts had somehow launched him forward.
the end result was Ben knocking himself loopy in any case and declaring himself the poopiest big dumb baby ever, a title everyone could agree he deserved and many doubted he would have a challenger to the crown.

Ben came out of la-la land with a squish, and realized that he was on a teeter totter with Gwen, and might of been so for awhile. his hands were gripping the hand hold and despite his best efforts he could seem to let go. 
"hey, look who back! have fun in la-la land smelly?" Gwen asked, smirking. "you were babbling on and on about how stinky diaper smushs..how did you put it.. oh! 'Da bestest fing evar! Gwen, pwease pway wiff me and wet me smush mah huggies!'" Gwen said, switching to a unflattering derp sounding voice while quoting Ben. 
"T-There is no way I said t-THAT!" Ben huffed and then cried out as Gwen bounced up, making him land hard with anther gross squish. 
"Hey, I have MORE then enough witnesses to prove I'm not lying, even if they are staying out of the stink zone." Gwen said, looking over her shoulder, keeping the fun going. "Back me up guys!" she called.
The kids who had stayed laughed and nodded and confirmed her story and Gwen turned back to Ben who was getting a little green in the face from his bouncing. 
"see? And honestly, i think i deserve a BIG thank you for doing this, it's not exactly easy being around you when you smell like a dumpster full of dirty diapers." she said, making a disgusted face. 
"I..I.." bounce and lift. "I'm Sorry for.." bounce and lift. "M-making you smell this.." Bounce and lift. "H-How long do I have left in-" Bounce and lift. "Diapie?" Ben asked, the diaper felt like it was on it's last legs and he could see a clock around to see the time and wasn't sure how long he'd been all derp.
truthfully Ben's time in the diaper was up, he'd been out of it for a LONG time, having gone down a slide and having begged for stinky diaper spankings, a act that had gotten some kids taken home by parents and others to have just decided the fun had passed their kink threshold.
"You've got about anther 15 minutes left." Gwen lied. "Do you think you'll be able to make it or just want a change now?" 
"I..I..I wanna try and tough it out.." Ben mewed.
he could make it 15 minutes, he was sure of it and then this would ALL be over and he could just go home and take a long nap and forget about all of this.
"Hmm Ok, but on the off chance that diaper gives up, we better get you somewhere safe." She said, getting off of the teeter totter while Ben was up in the air and sending him crashing down Hard, almost sending him BACK into la-la land but somehow he held on.
Sucking on his thumb and doing a cowboy walk for lack of a better term, Ben let Gwen take his free hand and lead him towards the public bathroom and the crowd of left over kids parted out of the way.
"heh, Mosses doesn't have nothing on you huh stinky?" Gwen teased. 
Ben just whimpered and sucked harder on his thumb, drool going down his chin.
Once in the boys room Gwen directed Ben over to one of the potties and he stopped in front of it and turned, giving her a questioning look.
"Yeah i know, seems silly but hey, if you leak it'll go in there." she said. 
he pulled his thumb out to argue but Gwen just rolled her eyes and pushed him backwards, making him land with a squish and the diaper to force wedge itself into the bowl and suck up the water in there.
"Oh shut up, who cares what you think you stupid diaper filling baby!" She snapped.
"A-ah! Gweeeeen! the potty water i-" Ben went to say and Gwen pulled out a pacifier from the bag, with a nice large nipple that would keep Ben from being able to talk and popped it in, adding a enchantment to stimulate his nursing urge and he suckled away.
"you know Ben..when I planned this all out I never thought it would go QUITE this good. I almost think I never even needed to set you up to fail the way I did. even without my little magic trick You would of been crapping yourself and going all goo goo gaga." she sneered. 
Ben's eyes widened and he tried to say something, but only muffled noises came out.
"That's right 'hero'..You think you shit yourself THAT bad without a little help? it was Me all along!" Gwen laughed. "And don't think this is going away anytime soon, Do you know just HOW much you've been blowing up on social media? Your being labeled Bellwoods big baby dork!"
She held up her cell phone so Ben could see the posts for himself and the big stinky baby started to cry, and get up, the diaper making it hard but if he put in enough effort he was sure that he could manage. 
"Actually, I'm done with all of this. You just stink too much." Gwen said, taking out a clean diaper and putting it on the counter. "if you can manage to get yourself free there's a clean diaper to change into. or you can always go home with your ding-a-ling on display. But just to show there's no hard feelings and I still think your cute..in a stupid diaper shitting doofus way I'll leave you one last present." 
with that Gwen held up a hand and filled Ben's bowels one last time, then turned and walked away as he filled his diaper again, wedging himself in the toilet and sending him into la-la land. 
whether he would come out of it enough to just undo the tapes and free himself or would be found wasn't her concern anymore, and Gwen just hummed a happy tune as made her way home, eager to get a shower in to remove Ben's stink and then watch the fallout from her little day of fun. 

the end