A/N: A kinkmeme de-anon. OP asked for consensual ageplay as a form of catharsis for Arthur, with Alfred as the authority figure and Arthur as the one regressing. This is pretty far from my usual in some ways, but it was a good challenge. Human AU, because I couldn't quite wrap my head around the implications of ageplay for nations.

Alfred stomped up the stairs, doing his best to make his footsteps sounds angry and imposing. He had been surprised at first when Arthur had said he wanted to do this, unsure why anyone would want some of the things Arthur was asking for; still, in the end he knew that there was nothing wrong with wanting it, and he had agreed. Arthur himself had humored Alfred more than once, after all. Alfred made his way down the hall until he was standing before their bedroom door—or rather, Arthur's bedroom door for today. Alfred pounded on the door.

"Arthur! Are you in there?"

On the other side of the door, Arthur was pulling the bedsheets over his head and preparing to pretend as if he weren't there. He was pleasantly surprised by just how much Alfred was getting into his role, which was also making it much easier for Arthur himself to find the headspace he was seeking. As the 'responsible one,' being a recalcitrant teenager was something he'd never had the opportunity to do—not even when he really was a teenager. It was liberating for him to be able, for once, to say no, to not listen to orders, to go against his own best interests and to have someone else—someone he trusted—be responsible for the consequences. Arthur had been looking forward to today, and he was already starting to sink into his role. By the time he heard Alfred open the door and burst into the room, his stubborn facial expression was quite genuine.

Alfred easily spotted the Arthur-shaped lump under the blankets. He marched over to the bed, stating bluntly, "You're in big trouble, young man!" as he grabbed ahold of the covers and yanked them off in one swift movement.

With the sudden loss of his bedsheets, Arthur curled up on the mattress, his body unexpectedly cold without them.

Alfred continued, still sounding quite angry. "I just got a phone call from your high school. Why didn't you go to school this morning, Arthur?"

"I'm fucking sick!" Arthur tugged a pillow over his head.

Alfred gave Arthur's backside a hard, stern swat. "Watch your mouth! Or I'll wash it out with soap," he added as an afterthought.

Arthur stuck his head out from under the pillow. "I didn't go to school because I'm sick," he repeated in a much milder tone, as if he took Alfred's threat seriously. And why shouldn't he? For all he knew, the other man would follow through with it.

"Are you really, now?" Alfred sounded sceptical.

"Yes! Now will you give me back my blankets and let me sleep my fever off?"

Alfred raised an eyebrow. "A fever." He reached over and pressed a hand to Arthur's forehead. "Hm. I don't feel a fever. But I'll give you the benefit of the doubt." Arthur seemed satisfied with himself; that is, until he heard the rest of what Alfred had to say. "I'll take your temperature and we'll see if you really do have a fever."

Arthur removed the pillow completely and let his head fall back down onto it with a soft, if stubborn, thump. "Fine."

Alfred got up from the bed. "All right, I'll be right back with a thermometer." He left the bedroom and headed down the hall toward the bathroom, where he collected the things he was looking for. Finally, he re-entered the room and returned to the bed, setting all three of the items he'd brought onto the nightstand: a wooden hairbrush, a thick thermometer and a jar of petroleum jelly. Arthur's eyes widened, and to Alfred the expression looked genuine.

"Oh no you will fucking not!" This exclamation earned Arthur's ass another smack.

"Language!" Alfred raised his voice. "If you swear again you will end up with soap in your mouth." Arthur may have been in for more than he had bargained for when he'd asked for this. He shut his mouth. Still, Alfred responded to the incredulous look on Arthur's face. "It's the most accurate way to take someone's temperature! And you're gonna be in a lot of trouble if I find out you're lying. Now," he continued, "roll over onto your stomach."

Arthur complied this time, albeit reluctantly. Once he had positioned himself properly on his stomach, Alfred tugged down his pajamas and underwear until they were about halfway down his thighs, leaving Arthur's bottom exposed for what he was about to do. Alfred reached over to the nightstand, first grabbing the jar. He unscrewed the lid, then stuck his finger into the jar and gathered a reasonably-sized dollop of the petroleum jelly on his finger, then carefully closed the jar again using his clean fingers and set it back on the nightstand. Picking up the rectal thermometer, Alfred shook it a few times to get the mercury to go down before he spread the jelly liberally over the metal tip and a little further up the glass stem. Now it was ready.

Holding the thermometer in his right hand, Alfred placed his left on Arthur's ass cheek and used his thumb to spread him open. And what a pleasant sight for Alfred, though he wasn't about to do what he usually did to the tight pink opening which was now on display for him. Instead, he brought the metal tip of the thermometer up to Arthur's entrance, then slowly began to press it inside until he'd inserted about an inch of it.

Arthur sucked in a small gasp of air as he felt the cool glass stem of the thermometer sliding into him. It moved easily with as much jelly as Alfred had coated it with and was not uncomfortable, though Arthur could not deny that it was a bit embarrassing, Alfred seeing him like this. But he most certainly had wanted it or else he'd never have built up the courage to ask for it.

Alfred made him wait with the thermometer inside him for the full two minutes it took to get a real temperature reading. When the time was up, he spread Arthur again, removing the thermometer carefully. He squinted at it, holding it up to the light to read the temperature. "99.4," he said finally. "That's not a fever at all! You cut class and lied about it?"

Arthur snorted. "Why yes, yes I did."

Alfred's voice was gaining volume again. "Then you are in trouble now!" Without ceremony, he dragged Arthur across his lap. With the other man's pants conveniently already taken down, Alfred immediately gave that bottom a loud smack! with his open hand. Arthur let out a quiet whine. Smack, smack, smack! Not much reaction. Several more hard swats followed, and Alfred suddenly noticed the firmness that was gradually growing and pressing against his thigh. Alfred knew, of course, that Arthur liked this sort of thing, but he hadn't expected any kind of arousal in this situation. That wouldn't do, that wouldn't do at all, not right now. He halted his strikes.

"I can see this isn't getting through to you," Alfred said sternly. He reached over to the nightstand yet again, this time grabbing the wooden hairbrush he'd brought for just this purpose. "We'll see if this works better."

And work, it did. Just two good smacks with the hairbrush, and Arthur was squirming across his lap, any previous traces of an erection now vanishing. A third strike elicited a hissed "ow!", and a fourth even more squirming. The wooden hairbrush was stinging much more fiercely than Arthur had anticipated, with all the force of each blow concentrated in such a small area. Smack, smack! Another cry of pain, and Arthur's bottom had begun to turn a nice shade of reddish pink. The seventh strike drew forth a swear.

"Ow, shit!"

Alfred stopped spanking him, placing the hairbrush down onto the bed. At first, Arthur was relieved, and he heaved a harsh sigh. However, he was soon in pain again, this time from thick fingers grasping him by the ear. Alfred's voice was nothing but stern. "What did I tell you about watching your mouth?"

Shit was right.

Still gripping Arthur's ear, Alfred dragged him up into a standing position and lead him out of the room and right back down the hall to the bathroom, this time with a different goal in mind. Slamming the bathroom door open on its hinges, Alfred dragged the ever-belligerent Arthur into the bathroom by his ear, before shutting the door behind them and pressing Arthur against the sink. "Don't say I didn't warn you," he admonished, still in-character, as he opened a new box of all-natural soap. After taking the soap out of the box, he turned to Arthur, soap in hand. "What color?" Alfred broke the scene briefly, making sure that Arthur was all right with this as it hadn't specifically been discussed.

Arthur gulped slightly. "Green." Not that this was a kink of Arthur's per se, but he was already far into his headspace and if they were going to do this then he wanted realism. He missed the days when, if he made a mistake, he received a simple penalty and he alone would be the one to suffer for it. Life was so much easier back then… even when he was about to be punished. He did have quite the mouth on him in real life, as well—perhaps he'd been deserving of this for longer than he knew.

"All right." Alfred got a firm hold on the back of Arthur's shirt collar and bent him over the sink, the unspoken command being don't move. The stubborn "teen" seemed to have understood, and stayed more or less in place, even as Alfred reached around to turn on the faucet. He held the soap under the running water for several long seconds, allowing a nice lather to build up on the outer layer of the bar until Alfred was satisfied. He held the bar of soap up in front of Arthur's lips and insisted in no uncertain terms that Arthur had better open his mouth. Again, the "teen" complied—Alfred, observing carefully, realized that by now Arthur had sunk pretty deeply into his teenaged headspace. Good, he was taking Arthur where the man had wanted to go.

Alfred continued on, pressing the bar of soap between Arthur's lips. It was all-natural soap—he had thought this out beforehand—which wouldn't make Arthur sick in case some of it did get swallowed, but which produced a good, rich lather. He began to move the bar back and forth, sliding it in and out of the rebellious Arthur's rude mouth and making sure to rub it up against his tongue to make the bubbles good and thick.

As the soap was pressed into his mouth, Arthur gagged on its acrid taste. The friction between the bar and his tongue was producing surprising amounts of sudsy bubbles which felt as if they might make their way down his throat. He coughed and sputtered, the thick lather forcing its way out around the bar of soap and down his chin as Alfred continued its motion in and out of his mouth. A single tear spilled down Arthur's cheek.

"Have you had enough?" Arthur couldn't tell exactly if Alfred's question was a rhetorical one or not, but he nodded anyhow in the hopes that his punishment would soon be over with. "Have you learned your lesson about swearing?" Another nod. Alfred released his grip on the back of Arthur's head and pulled the soap from his mouth.

Not needing any prompting, Arthur immediately began to spit the good amount of lather which had collected in his mouth into the sink, sputtering and allowing even more of the suds to drip down his now-reddened chin. Still unable to get the taste out of his mouth, Arthur turned on the faucet and cupped his hands beneath the flow of water, first splashing the clean water on his mouth and chin to clear away the froth and then sloshing some around in his mouth to get rid of as much of the bitterness of the soap as possible, though a thin layer of soapy residue seemed to coat his mouth no matter how hard he tried to rid himself of it. Having done the best he could to clean himself up, he looked over expectantly at Alfred.

"Now that your mouth is clean, I think I deserve an apology," was Alfred's response. At first, Arthur's face contorted with distaste for the idea, but rather than risk more soap, he decided to humor Alfred.

"'M sorry," he muttered unconvincingly.

Alfred's facial expression remained stern, though his voice became slightly more gentle. "Sorry for what, son?"

Arthur's eyes widened briefly at that last word, and he finally heaved a sigh and spoke up. "I'm sorry for swearing." A beat. "And for skipping class, and lying about it." His words now sounded more genuine somehow, and there was a youthfulness to his intonation which Alfred had never heard from Arthur before. "I'm sorry, dad…" The single tear which had overflowed previously had now become two, then three, and then suddenly Arthur's arms were wrapped tightly around Alfred, his face buried in the taller man's shoulder.

Alfred was startled at first, but his arms wrapped instantly around Arthur as he felt the other holding him even more tightly than usual. The smaller body in his arms shuddered a few times, and Alfred rubbed warm, soothing circles up and down Arthur's back as he cried. "It's all right, Arthur, I'm here… Daddy's here, Alfred's here." He was unsure which Arthur needed to hear, so he simply said both.

Arthur nodded, finally pulling away after a bit to wipe his eyes with the back of a hand. "Sorry, Alfred," he repeated in his normal voice, sniffling, though he seemed collected enough. "I did warn you that this sort of thing could happen. It doesn't usually, not for me, I mean, but, I don't know—."

"Shhh," Alfred drew Arthur back to himself, giving him a reassuring hug. "And I told you I'd be able to deal with it just fine if it did happen. It's okay."

Arthur allowed himself to be drawn closer, his rebellious persona melting beneath the warmth and tenderness of Alfred's touches. Eventually, he breathed, "Thank you. Thank you, Alfred. Dad," and with this word he smiled up at Alfred, and the other man couldn't help but to smile back.

Alfred reached up and ruffled Arthur's perpetually unruly hair with his hand. "Hey, don't worry about it. I wanna take care of you, and if that means doing stuff like this, I'll down with it." He patted Arthur on the shoulder, "Plus, you did really well. I'm proud of you, son."

And he immediately found himself squeezed in an even tighter hug than before.