Matti squirmed, though it was hard for her to tell how much of that was out of anxiety, and how much was because of how very turned on she was by all this. Every time she tried to think of a way out of this, an avenue of escape, she found a dead end, and that made her all the more nervous about how it was going to end, which, in turn, made the situation even hotter to her, as much as she hated to admit it.

How many people in stories who had gotten to this point were ever able to get away? This was it, the point of no turning back, and, try as she might, she couldn't think of a single one who avoided plunging head-first into it once they were led to it, even those who knew what they were getting into if they did. It was like their diapered fate was a whirlpool, dragging them in, the currents reaching out and pulling them towards its center from even further away than it looked. The very 'choice' itself was just a part of the point of no return.

She blushed, those thoughts making her want to reach down and rub her diaper, or straddle the arm of the couch, or one of the pillows on it, and start humping. This had always been one of her favorite parts of a diaper story, seeing the protagonist face their fate and fail utterly to do anything to stop it no matter how hard they tried, but being in it herself meant she couldn't afford to enjoy it as much as she might have otherwise, even assuming that Kiara wouldn't punish her for it, since that was not something a good little girl would do, Matti guessed.

"C-Can I at least have some privacy?" she asked, mind racing, eyes darting over to her skirt, still lying in a heap on the floor. That probably wouldn't help her get away, especially not if Kiara had noticed what she was looking at and took the skirt with her, but it would be easier to think of her options if she didn't have the girl watching her every move. "I-I don't know if I can go with you staring at me."

"That didn't stop you from peeing your pants," Kiara pointed out. "Besides, I want to see it. I bet you're going to be so cute, squatting down, pushing so hard!" Matti's face blazed even hotter. "And, you know, I want to be sure I get a good video of it so I can rewatch it whenever I want. Or show it to my mom if you give me some reason to."

"Why would I do that?!" Matti squealed, shivering at the thought of her professor watching her poop her Pampers. She couldn't let that happen, no matter what! She eyed Kiara, taking her in, confident that she was one of the few people even relatively close to Matti's age that she'd have a chance at overpowering. Was Dr. Osswald really going to help keep her from flunking if she beat up her daughter when she was meant to be tutoring her, though? She very much needed to not fail. Was it worth this, however? Giving Kiara something she could hold over her head indefinitely, and use to make her do anything and everything she wanted?

"You're going to do it because I already have plenty of other videos of you that I bet she'd find very interesting," Kiara told her. "This will just be the icing on the cake."

Matti gulped, thinking back to everything else that had happened here today, how she'd been playing with the doll when she was meant to be tutoring Kiara, how her one attempt to actually help her had crashed and burned, how she'd wet herself, how she'd spent quite a while happily sucking on a pacifier. How many of those had Kiara been able to capture on her phone? They would be embarrassing enough on their own, but the girl could, and likely would, probably edit them to take out all context, any explanation of why they were happening, and make it look like Matti had chosen to do all of that. The girl was definitely smart enough to know not to show what textbook Matti had been struggling with, so it would seem like it was one of Kiara's, and not one of the professor's own, and even if Matti tried to tell the truth, it would be her word against Dr. Osswald's own daughter's.

There was no way out. She'd been caught in the whirlpool, or the jaws of the trap were closing around her ankle, or the cell door was slamming shut and locking behind her. Whatever way she wanted to look at it, she was trapped, outmaneuvered by this younger girl, helpless.

"B-But..." she stammered, shaking her head.

Kiara grinned, as if she could sense Matti's defeat. "That's right," she cooed, pushing the pacifier back into Matti's mouth and lifting her phone. "Go on, sweetie, time for your butt to do its thing."

Matti felt herself start to suck automatically, hugging the doll to her chest, instantly turning into more and more of a toddler, powerless against her older, teenaged babysitter. She was no match for her already, and as soon as she did what the girl wanted, that was only going to get more true. Once Kiara had a video of her filling her pants like a baby, there wasn't going to be anything Matti could do to stop her from making good on her plans, to keep her from turning her into a frilly party dress wearing, tea party throwing, princess loving little girl.

Matti gasped as she felt a mushy mass beginning to form in her diaper, realizing to her horror that it had already begun. Had she been holding it for too long, after that bottle Valerie had fed her this morning? Or was this a dark part of her brain eager to see her squirm in the face of the fate Kiara wanted for her, that wanted to see her like all of those other diaper story 'heroes' as she took this last, biggest step back into babyhood?

"N-No!" she shook her head, trying to stop it, concentrating with all of her might, doing everything she could, only to find that none of it was enough. Now that it had started, there was nothing she could do, no way for her to halt the onslaught of warm, soft mess that was slowly filling her pants. No, not her pants. Her Pampers. She was thoroughly pooping her Pampers, feeling them swell and grow around her as she sucked her paci for comfort, her tutee gleefully recording the whole thing.

Valerie had, of course, made her use her diapers plenty of time during their training sessions, but this was different somehow, whether that was because it was somebody else, somebody younger than Valerie, smaller than her, that she should have been in a position of authority over, or whether it was knowing that these were, in fact, baby diapers, which made the act feel so much more infantile. She was, literally, a Pamper-pooper now, and that was one thing, lately, that she was able to say she was excelling at. Her grades might be plummeting, and she might be struggling to keep up with the real cheerleaders at practice, but, thanks to the fiber she'd been given that morning, she was filling her Pampers to the brim. How was she ever going to be able to seriously think of herself as an adult, as a college senior, mere months away from going out into the real world, again after this?

"Wow," Kiara giggled. "If this is you when you 'd-don't hafta go,'" Kiara made her voice more high-pitched, mocking Matti's earlier protests, "I'd hate to see what happens when you do."

Matti sniffed and pouted, cuddling Mattix harder, as if she could hide behind the doll and disappear. She really did match the doll now, she thought, wiggling her bottom, nose wrinkling as the mess shifted and squelched. And she'd guaranteed that, from now on, she was going to be Kiara's own doll, to do with, and play with, as she pleased.

"All done?" Kiara asked, stepping over and giving the back of Matti's diaper a poke. "Oh, wow!" she exclaimed, patting it, ignoring Matti's complaints as she did. "That's so gross!"

"Y-Yeah, it is!" Matti nodded, seeing an opportunity and taking it. "It's so gross! T-Trust me, once you clean this up, you're going to change your mind about this whole thing!"

"We'll see about that," Kiara shrugged, though Matti had to admit, she didn't seem all that worried about it, her words seeming to be more about teasing Matti than anything. "For now, I think you're ready to change Mattix."

Matti whined. "C-Can't I..?" she asked, looking down at her own diaper.

"You've made her wait for long enough already, young lady!" Kiara scolded. "If you put it off any more, she'll probably get a rash, and then she'll be crying all night! Do you want that?"

Despite everything, Matti saw a glimmer of hope. "Maybe I do," she crossed her arms. "Maybe it'll teach you a lesson to have to listen to her all night long!"

"Don't be silly," Kiara said. "Mattix is your dolly now. You need her to show you how to be a good girl." Matti blushed as she heard that, remembering that, of course, Kiara controlled everything the doll did, so of course it wasn't going to cry for any longer than she wanted it to, making Matti's threat meaningless even if Kiara had kept it for herself. "And you are going to be a good little girl, because I can see on my app how long you let her cry, and I'll make sure you regret it if you take too long to take care of her."

Kiara was, essentially, forcing Matti to take the doll with her wherever she went to avoid that. And, since Kiara could make the doll do anything she wanted, she could make her play with her doll at any time. Worse than that, though, Kiara could make the doll use its diaper any time she liked, which Matti had no doubt meant that she was expected to follow suit immediately. As Kiara had already told her, whatever the dolly did, she did. Kiara was, in effect, controlling Matti through the doll, like a high tech voodoo doll whose main goal was to turn her into more and more of a little girl.

"Kiara!" Matti sniffed. "I can't do that! I'm in college! I have more important things to do than...!"

"It really sounds like somebody wants little Mattix to get diaper rash," Kiara interrupted. "Feel free, I suppose. It won't bother me if she cries through the whole night."

It would bother Matti, obviously, and it would definitely bother Valerie, too, and guarantee that she found out about the doll, which Matti was sure she would find quite amusing. Already, Matti knew she was going to have trouble when she showed up not in her Pull-Ups, but in a Pamper. She had no way of proving that she'd been able to keep her Pull-Ups dry, especially because she hadn't, so she was certain she'd be wearing them again tomorrow. She had no idea how she was going to explain the sudden appearance of a doll that had a shirt that matched the one Valerie had 'given' her that morning.

"Fine," Matti sighed. "I'll change her first."

She knelt down, every movement giving her a fresh reminder of the mess she'd made, of how completely infantile she must look now. And, really, how infantile she must be, to have done that, to have let herself be forced into it by someone like Kiara. She really did feel like a toddler playing with her dolly as she sucked on her pacifier, unfastening the diaper and opening up the tiny, toy package of baby wipes. To her surprise, there was one in there, ready for her to grab it.

Like with the 'wetting', the doll's mess was all in the diaper itself, as she suspected that the color would change back to normal once the diaper was washed, like it had with the last change. She wasn't sure if the baby wipe was necessary or not, but, at least with Kiara watching her every move, she knew better than to forgo it, running it over the doll's smooth crotch before stuffing it back into the package for next time.

Next time. She shuddered, thinking of that. Was she going to have to do this regularly now? Pretend to change this stupid doll's diaper, quite possibly while she, herself, was in a 'matching' one?

"Good girl!" Kiara praised her. "Now, here's a clean one."

Matti slid the diaper under the doll's bottom, picking up the tiny can of baby powder to pretend to sprinkle it before fastening the diaper up. "See?" Kiara smiled proudly. "I knew you'd be a good little mommy for your dolly!"

Matti blushed and rolled her eyes. "Whatever," she mumbled. "C-Can I get a clean diaper now, too?"

A wicked grin spread across Kiara's face as she cheerfully declared, "Nope!"

"Why not?!" Matti whined, glaring up at her.

Kiara giggled. "Well, Skylar could only find one this time, so I'm afraid I don't have any to change you into."

"What?!" Matti squealed. "B-But... Wh-Why did you make me use it, then?!"

"I didn't," Kiara shrugged. "Mattix did. She's the one who had an accident, and you're the one who loves her so much that you just had to match her."

Matti could hardly believe what she was hearing. "No, she didn't!" she fumed. "You made her do that! A-And you made me..!" She thumped her hand against the floor in frustration, which only grew as she realized what this meant. "D-Do you have something else I can change into, then?" she demanded. "I can't walk back to my dorm like this!"

"You can always wait for my mom to get home," Kiara smirked. "I'm sure she'd be happy to drive you."

Matti narrowed her eyes, knowing that the girl was daring her to call her bluff. She couldn't want that to happen. That would take all of Kiara's power away. Those videos would be useless if Matti let Dr. Osswald see her in diapers, especially dirty ones, in person. But Kiara knew, despite that, Matti would never in a million years let that happen willingly, even if it meant doing what she'd just insisted she wasn't capable of.

All she could do was pull her skirt back on, nervously trying to adjust it to keep her sagging diaper hidden, knowing that all it would take was the lightest of breezes as she headed to campus to flash her padding to anyone and everyone around her, while Kiara packed her messenger bag, putting in the doll and all her supplies.

"K-Kiara," Matti sniffled as the girl slid the bag over her shoulder. "I-I bet our sizes aren't that far off. C-Can't I just borrow a pair of your underwear, and...?"

"No way!" Kiara swatted the back of Matti's diaper, chuckling at the older girl's disgusted reaction. "After this little accident, I don't think I'll ever be able to trust you in big girl panties again, young lady!"

"B-But you..." Matti protested.

"You're right," Kiara cut her off. "I've never even seen you in big girl panties, have I? I guess that just goes to show that you couldn't possibly ever be a big girl, could you?"

"Yes, I am!" Matti insisted, stomping her foot, but it was hard not to feel like the laugh Kiara gave in response was, in fact, the correct reaction. How could she be a big girl when she was standing there in a very poopy Pamper, dolly, and pacifier, tucked safely away in her bag like prized possessions?

"I'll see you next time, Mathilda," Kiara told her, giving her one final pat on the diaper to send her off. "And don't even think about trying to skip! You know you need all the help you can get!"

It was hard to remember that Matti had, in fact, been sent there to help Kiara, that she was meant to be tutoring her, not being taught to be a good little girl. She definitely wasn't going to try to remind Kiara of that fact now. All she could do was blush, and adjust the strap of her messenger bag, and mumble a quiet, "Y-Yes, ma'am," proving to both of them just how well her first lesson had gone.

Epilogue

Matti took a deep breath, bracing herself before she stepped into the door. She hadn't noticed the little drugstore on her way to Dr. Osswald's house, but, as she shuffled back, trying to decide whether to take her time as she walked, to help keep her tiny skirt from fluttering up and showing off her diaper too much, or to hurry and see if she could beat Valerie back to their room, not that it would matter since she didn't have a key to their room, she'd spotted it, over on the other side of the street, a beacon of hope.

Maybe, if she was lucky, they'd have Pull-Ups there. It was hard to tell, since it was pretty small, but she had to try. She didn't want to let Valerie see her in a messy diaper, not after that threat from this morning, but she also didn't want Valerie to see her in Pampers, didn't want her to know that she fit into baby diapers. She had no doubt the cheerleader would tease her relentlessly for that. And she'd want to know where Matti had gotten it, too, which would mean Matti having to tell her the whole story of how she'd gotten outsmarted and diapered by the girl she was supposed to be tutoring.

The tininess of the store worried her in more ways than one. Not only was there a chance they'd only carry medicine, and other basics like that, the smell of her diaper would be hard to hide with so little space if there were any other shoppers nearby to pick up on it. She'd waited outside for a few minutes to see if she spotted anybody going in or out, but, finally, she'd reminded herself that standing out here in the open while she hoped for the perfect, private opportunity to shop wasn't much better.

The bell over the door rang, far louder than she would have liked, making her wince as the eyes of the one worker looked over at her and smiled. It was an older woman, or at least one older than Matti, though, in the moment, it felt like anyone over the age of five qualified as being older and more mature than Matti. She was tall, and pretty, and there was definitely something about her that seemed familiar, although Matti couldn't quite place what. It was enough to make her worried, however, almost sending her dashing back out the door, not wanting anyone she knew to see her this way.

But, other than her professors, she couldn't think of anyone she'd met, or interacted with on a regular basis, this age. And, after a moment, she realized what it must have been. The red and white striped apron the woman was wearing reminded her of the one that Ms. Emily wore, but, of course, that had been in a whole different dimension. This couldn't be her! Right? She did have the same short, brown hair, too, and the more Matti stared, the more similarities she found, making her more and more uncertain.

"Hello, there!" the woman called pleasantly. "Do you need some help, dear?"

Matti swallowed, shaking her head to clear it, and to answer. It couldn't be Ms. Emily. Matti couldn't imagine her working at a place like this, and she definitely would have recognized Matti, and probably would have spotted her diaper, too, even through her clothes. It was a coincidence, that was all. Or maybe this was her own universe's version of Ms. Emily, someone who simply worked at a drugstore, rather than running a daycare for adult babies. "I-I'm fine," she managed to croak out, scrambling down one of the small aisles.

There wasn't much to look at, which made it all the more awkward, trying to avoid the woman's stare. She had gotten lucky in that there were no other customers, but that also meant there was nobody to distract the woman, to keep her from seeing Matti pretending to browse, and nobody else to blame the scent of her stinky diapers on if she dawdled for too long.

Perhaps it would have been better if there wasn't a diaper section, and she could have left and never came back. But, sure enough, the last aisle she meandered down was fully stocked with everything she could need, including her Pull-Ups. She hesitated in front of them, having seen that there was, of course, no self check-out here, and, even if there had been, no way that the worker wouldn't have seen what she was buying anyway. What else could she do, though? No matter what she looked like, this woman was a stranger, and it would be far better to deal with her than Valerie.

"Here we go!" Matti declared, plopping the package of Pull-Ups down on the counter. "This is all I need!"

"Well, it's a good thing we had them, then," the woman smiled.

"O-Oh!" Matti blushed bright red, realizing what she'd said. "I-I mean... I-I don't need them!"

"Do you want me to put them back?" the woman asked.

Matti shook her head desperately. "No! N-No, don't do that! I-I need to buy them, but... Th-They're not FOR me, obviously!"

The woman chuckled in a way that made Matti unsure whether she'd bought that or not. "Of course not," she said, her tone still not making it clear. "Are you helping potty train your little sister? That's very kind of you. I'm sure your parents appreciate the help!"

"N-No," Matti shook her head again. "I-It's not that! I-I'm... babysitting!" She blushed, recalling how Kiara had told Skylar that she was babysitting Matti, surely why that excuse had popped up, since that wasn't an activity she normally thought about in any way.

"How responsible of you," the woman nodded, Matti not wanting to ask if that was because she had assumed Matti was too young to be a babysitter.

Matti paid for the Pull-Ups and took the bag with them, though she instantly knew that she didn't want to walk all the way back to campus carrying them, seeing how the top of the package peeked out over the shopping bag, advertising to everyone what she was carrying. And what if she ran into Valerie on campus? Not to mention the fact that she was desperate to get out of this messy diaper. "H-Hey, I don't suppose you have a bathroom in here, do you?"

The woman happily pointed it out, and Matti scurried over to it. It was small, too, and she was certain the woman would be suspicious if she looked in the trash can and found a dirty diaper there after Matti left, especially with how long it took Matti to get herself cleaned up properly in there, but she wasn't about to take the diaper with her and hope she found somewhere else to dispose of it. She stuffed it into the trash can, putting the Pull-Ups package on top of it in an attempt to hide it, after putting one on, and being grateful for the clean padding and how relatively thin it was, and stuffing the rest into her bag.

She'd hoped that there would be another customer by the time she left to distract the woman, but it was still only her. She blushed, shuffling towards the door, heart pounding. "Hey!" the woman called as Matti reached for the door.

Matti froze, turning, reaching back automatically to adjust her skirt, terrified that she'd gotten the hem caught in the waistband of her Pull-Up, somehow, despite having spent far too long examining herself in the mirror before stepping out of the bathroom. "Y-Yeah?" she squeaked.

"Good luck with that potty training!" the woman smiled at her with a wave. "See you next time!"

"Y-Yeah," Matti nodded, waving back, wanting to tell herself that she would never come back here again, but knowing that there was a chance she might need to make another pit stop here in the future, thanks to Kiara. "Th-Thanks."

She hurried back to campus. After making part of the trip in a dirty diaper, she had to admit that she felt far more comfortable running around in this skirt with just a Pull-Up underneath it. There was still a risk of flashing it, but it was so much less than the risk of showing off her Pampers, and the results would be so much less humiliating, that it almost felt silly to worry about it.

By the time she returned, Valerie had, of course, made it back to their room, though Matti didn't mind that so much now, since it meant being able to get right in, rather than having to wait. And, when Valerie lifted her skirt to check her, her Pull-Up was nice and dry, exactly as she'd said she wanted that morning, and had almost definitely not expected Matti to be able to accomplish.

"Huh," the cheerleader mused, poking at the padding. "You actually did it."

"Well, yeah," Matti said smugly. "I'm not a baby!"

"Hmm," Valerie raised an eyebrow, then narrowed her eyes. "Wait a second... Is this the same one I sent you to class in?"

"Wh-What?" Matti gulped. No way! How had Valerie known?! Matti looked down at herself, at the training panties she was wearing. Suddenly, she wasn't so sure about the design she'd picked out of the package, and whether it had been the same one Valerie had chosen that morning, and she felt her knees begin to shake, certain that, despite everything, she'd doomed herself with a stupid mistake at the last moment, probably earned herself a spanking, if not a more harsh punishment. "O-Of course! I-I can't get into our room, so where else would I have gotten..?"

"There we go," Valerie grinned, stroking the Pull-Up as Matti felt her bladder giving way a bit, letting out a trickle of wetness in her panic. "Looks like somebody is going to have to wear Pull-Ups tomorrow, too!"

Matti really couldn't complain, considering that she'd wet herself right in front of the girl. And, more importantly, considering that she'd almost had to face her in a messy diaper instead. It was probably for the best, honestly, to have a little padding, just in case Kiara made the doll wet itself, and expected Matti to do the same, while she was in class or something.

For now, though, Matti was happy to go get dinner, and then come back to her room to be put to bed. It was early, but after the day she'd had, she didn't mind so much. She also didn't mind being given her nightly bottle, despite her suspicions that the girl was drugging her with it, and despite the form it always took, with Valerie making her drink it from the strap-on harness around her waist.

"Look at you," Valerie praised her, patting her on the head. "So eager tonight! Are you just that thirsty?"

Matti blushed as she realized what it actually was, her mind drifting to the pacifier tucked away in her messenger bag, and how much she'd liked it. The nipple of the bottle wasn't quite the same, but it was similar enough that, now that she'd tried a paci, and found out how nice that could be, she found herself treating it the same.

"Or did somebody finally have a little breakthrough in her training?" Valerie asked. "Look at you go! I think you might be almost ready for the next stage!"

Matti had no idea what that meant, and that did scare her, wondering what else Valerie could have in mind for her. For tonight, however, all she wanted to do was finish her bottle and get tucked in so that Valerie would go do something else, hopefully before Kiara made the doll cry and alerted the cheerleader to its presence and forced Matti to explain where a tomboy like her would have gotten something like that.

It had been hard enough, dealing with Valerie on her own. Now she had Kiara, too, trying to make her into a baby in a completely different way, and having proven already that she might just be able to succeed at that. What chance did she have, going up against one of them, much less both, especially when, deep down, she knew that there was a part of her that wanted them to win, to turn her into a diaper slut, or a girly baby girl, just like the characters in the diaper stories she loved so much. It had been a long day, but she had a feeling that it was nothing compared to what was going to come next.