The Baby of the Family (Patreon)

An anonymous caption commission. Picture property of AdultBaby.xxx. 

Ava had been hesitant to take the job at first, for quite a few reasons... While she liked kids, and taking care of them, being a live-in nanny was much different than just popping in once or twice a week. The money was good, especially when she didn't have to worry about paying for an apartment, but it meant giving up some of her independence, since she would be on-call most of the time. And, probably hardest to get used to of all, Emily was not really a baby.

In fact, the girl was around Ava's age, despite the thick diapers she wore to bed, and sometimes during the day. More commonly, she was in training panties during the day, which meant a big part of Ava's job would be escorting Emily to the potty. Emily's Mommy had confided in her that she doubted the girl would ever get beyond that point, and might even backslide further in her potty training, so unlike with a real toddler, if Ava took the job, she would be dealing with that the whole time, with no real relief in sight.

She eventually took the job, though for the first week or so, she wasn't sure why. It was strange, waking up another person her own age to change her wet diapers in the morning, bathing her, seeing her wiggling in front of her - hands clamped desperately to her crotch - begging for the potty. The more she saw of it, however, the more she realized there was something fun about it, something she enjoyed observing, and being in charge of.

Perhaps it was the thrill of being in charge... Ava had always been the baby of the family, the youngest of three, so she'd always had an older sibling around at home to boss her around, and being the smallest physically as well, there had never been much she could do about it. Now, however, she was the one that Emily had to listen to, no matter what. She had total authority over the girl... She was allowed to put her in the corner, wash out her mouth with soap, even spank her if she saw fit.

While she was happy to find excuses to try out all of those, she wasn't completely satisfied. How far would Emily's obedience go? She decided to test it out one day when the girl rushed up to her and begged, "Can I please go to the potty?"

Ava shook her head, focusing on the TV. "No."

"What?!" Emily whined. "B-But... I really have to go!"

"I'm busy right now," Ava shrugged. "Hold on a minute."

But Emily had been coloring, and Ava knew, when she was doing that, she waited as long as she could before she had to tear herself away. From the corner of her eye, she watched the girl whimpering and squirming beside her, not wanting to make it too obvious she was paying attention to her, despite wanting nothing more than to take in the whole spectacle. Finally, she heard a gasp from the girl, and she reached out, pushing aside Emily's hands and pressing her own to the padding around her waist, feeling as it grew softer, warmer beneath her hands. If she thought about it too much, it was kind of gross, thinking about what was happening, yet it was simultaneously incredibly empowering, knowing it was happening because of her, because she'd said no. "What did you do?!" she demanded, having to hide a grin as the girl sniffled guiltily. "I thought you were a big girl!"

She had to write down the failure on Emily's potty training chart, of course, along with all the others, in the days to come. Emily tried to tattle on her, but she was known to be a bit of a drama queen, so her Mommy believed her when Ava said the wait was no more than a few seconds. Before long, Emily was back in diapers, despite the tantrum she threw over it, and the spanking her Mommy gave her in response.

Ava was told she still had to take the girl to potty when she had to make her poopies, but by now, she couldn't bring herself to do it. Emily seemed to suspect as much - or she was just humiliated at having been railroaded back to diapers by her Nanny - and waited quite a while before asking Ava for the potty, likely trying to wait until her Mommy got home. Ava, unsurprisingly, was just too busy, though not busy enough not to grab the girl's arm when she tried to stalk away at the denial, holding her in place until she let out a mortified groan. Ava pulled the girl over her lap, holding her in place with one arm while the other pushed solidly against the bulky diaper. "Emily, you wouldn't dare! Only a baby does this!" she teased, feeling as the gooey mass pushed out beneath her fingers.

Emily got better at timing it to make sure her Mommy was home, but the whole thing had just been too deliciously humiliating for the girl... Ava finally went out and bought some suppositories, slipping them into the girl's bottom during one of her changes to make sure she could experience it again. Ava knew Emily didn't dare go without asking, because if she did and Ava reported on it, Mommy would think she'd completely lost control, and take away all her potty privileges. She tried to tell Mommy what Ava was doing, but that just made it look like she was making excuses for her accidents... Either way, Ava was sure the girl was days away from being demoted to full baby, and it was - at least mostly - because of her. She'd never felt so powerful...

Then, one day, as she slipped a pair of suppositories into Ava's bottom, she heard a throat clear behind her. Her eyes widened as she turned, gulping, knowing she'd been caught... Sure enough, Mommy was standing there, shaking her head. "What exactly are you doing?!" she demanded. Ava stammered, wordless even before Mommy pulled out her phone, playing a slightly fuzzy video that was definitely clear enough to make out her telling Emily no the day before, then probing at her diaper as it ballooned outwards.

"I-I was just curious!" Ava finally managed to get out.

"I can help you with that," Mommy told her. "Go ahead, finish diapering her... The damage is already done..." Ava nodded, going back to her work, hands shaking as the woman stood behind her, watching the whole time. When she was done, and Emily crawled off the table smugly, Mommy grabbed Ava, lifting her up onto the table and stripping her. Ava sniffled, cried, begged, but none of it stopped the woman from pushing three of the suppositories she'd bought for Emily into her, then swaddling her in a thick, overnight diaper and one of Emily's more babyish outfits.

"I can't believe I didn't believe my sweet baby," Mommy shook her head. "I'm glad I finally got suspicious enough to put up that Nanny-Cam yesterday. How long have you been doing this?"

"J-Just yesterday and today," Ava lied. 

"Oh, Ava," Mommy sighed, pushing one of Emily's huge pacifiers into Ava's mouth. "Do you really expect me to believe that?" Ava squirmed under her glare, letting out a shuddering gasp as a powerful cramp wracked her system, and it fully dawned on her that she was the one who was about to mess her diaper this time. "Why don't you two squat down?" Mommy suggested. That was about the last thing that Ava wanted to do, with her guts churning the way they were, but the woman wasn't going to take no for an answer. "Don't be scared of each other... Go on, right next to each other... No, not that way..."

Ava's cheeks burned as the woman positioned her, diapered bottom against Emily's diaper. "You were so curious about what Emily's poopy diaper felt like... Well, you can feel that all you want, but only while you make your own... And only for today." Sure enough, Ava could feel something pushing gently against her padding from the outside... But, somehow, feeling it there, knowing she was about to feel the same on the inside of her diaper as well, it wasn't quite as empowering. "Emily was doing so well with her potty training before you came around... I can only assume now that you're the reason she started having so much trouble. So, I'm going to let her try big girl panties to see how mature she really is now... Of course, I didn't expect her to make it that far so soon, so I don't have any for her, but I'm sure you know where I could find some, don't you?"

Ava was sweating, desperate not to let go, even though the objects inside her were soon going to make that impossible, so it took her a moment to realize Mommy was referring to her own underwear drawer. "N-No!" she gasped. "They're mine!"

"Don't you worry," Mommy smiled down at her. "We have plenty of diapers for you to wear instead. And since you'll be in those, while Emily will be in big girl panties, I think she'll have to be the one in charge from now on. She'll be in charge of training you... If you want to get out of your diapers, you'll have to prove you know when you need the potty by asking her for it, but you're not big enough for potty privileges yet, so you'll still have to use your diapers until we're both sure you're ready to try for trainers. That should only take... Oh, a month or so, then we can try to let you use the potty to make your messies, then, eventually, for your pee-pee, and then, after that, maybe, just maybe, you can have training pants. But if you use your diapers at all without letting one of us know first, and going in front of us, we'll just have to assume you need them, and cancel any plans for training."

Ava shook her head, whimpering at the thought of the stupid baby Emily in charge of her, in her underwear, while she was toddling around in diapers. "N-No! They're mine! She'll ruin them!"

"She might," Mommy shrugged. "If that happens, we'll just have to throw them out, and neither of you will get them... And if it happens too often, she'll have to go back in trainers, and I'll get a new Nanny for both of you. But make no mistake, Ava... Even if that happens, you're still the baby of the family now."

Ava let out an involuntary grunt as her tummy contracted, pushing a load of warm mush into her diaper, pressing back against Emily's diaper. She squirmed, wrinkling her nose, especially when she realized that was just the beginning - not only of this mess, the first of many, but of her new life back as the youngest. She'd gotten to be in charge for a little while, but not long enough... She'd abused her power, and now she was back where she apparently belonged.