Work Text:
Katsuki had been a good boy all week. There /had/ been moments where he wanted to throw a tantrum or argue with his Daddy. But, what made him reconsider and restrain himself, was a deal that his Daddy had made him at the beginning of the week.
Izuku said that if Katsuki could behave from Monday until Friday, he’d buy something for him at his favourite toy store. Katsuki hadn’t been to the toy store in awhile and he was dying to go again. Their busy schedules always got in the way though.
It was finally Saturday morning and Katsuki was buzzing with excitement. He knew that if he made them breakfast early, the sooner they could go. So, he was currently in front of the stove, making a quick breakfast of bacon and eggs.
Izuku walked into the room, fully dressed and ready for the day. He sat down at the counter, watching Katsuki cook.
“So when are we going?” Katsuki turned around from the stove to ask him, barely containing his uncharacteristic excitement.
“We’re going somewhere?” Izuku cheekily asked back, feigning surprise. Izuku knew what his baby was referring to, but Izuku loved to tease him.
Katsuki scowled back at him, his eyebrows furrowing. “You made me a promise remember?”
“Oh yes...I did, didn’t I. Let’s see, were you good all week?” Izuku put a hand on his chin in thought, taking more time then he actually needed to “think” it over.
Katsuki /had/ been very good when he was little this week. Izuku could tell when he was on the verge of being bratty, but the temptation of a new toy won after all.
Izuku never usually made these promises as he enjoyed when Katsuki acted like his usual self, but Izuku knew he was going to have a stressful week that would leave him tired in the evenings. When he was tired he always got a bit grouchy and he didn’t want that to affect his and Katsuki’s play time.
“I can’t recall a time when you were bad, so I guess we can go.” Izuku finally answered.
Katsuki smiled widely, not even trying to hold back his excitement now. He turned back to the pan on the stove, checking the bacon.
“Can we go after breakfast?” Katsuki asked.
“Yes, we can.” Izuku replied, not wanting to tease him anymore as he liked seeing his baby so happy.
All throughout breakfast, Katsuki had a little smile on his face. He also ate quicker then he usually did, probably trying to get out of the house sooner. When he was done, Katsuki jumped out of his chair, grabbed his plate and quickly placed it in the sink.
“Okay, I’m going to go get dressed.” He left the room, not even waiting for a reply. Izuku chuckled.
Katsuki grabbed a clean shirt and pants, hurriedly throwing them on. He brushed his teeth and quickly pulled a comb through his spiky hair. Izuku walked into their bedroom, sitting on the bed, waiting for Katsuki to finish.
“I’m all ready. Let’s go.” Katsuki announced as he went to the door of the bedroom, prepared to leave. Then Izuku’s voice stopped him.
“You sure?” Izuku questioned.
“Um...yes?” Katsuki’s red eyes narrowed.
Izuku frowned. “Baby, I think we should put a diaper on you. You might slip while we’re there and you definitely will be little when we get back. Then you might have an accident before I get one on you later.”
“I’ll be fine. I don’t want one right now.” Katsuki protested.
Izuku got up from his spot on the bed and went into the bathroom, Katsuki already knew what he was grabbing. Katsuki stomped his foot in annoyance. He didn’t want one! He could resist being little in the store, he knew he could. Izuku walked back into the bedroom with a diaper in his hands.
Katsuki crossed his arms across his chest. “I’m not putting it on.”
“Then we’re not going to the store and you’re not getting a toy.” Izuku matched his tone.
Katsuki’s voice raised. “What?! That’s no fair! I was good all week!”
“I know how you get when you’re in the toy store. Just listen to me and I’ll buy you something you really want.” Izuku’s voice was softer now, trying to calm Katsuki down.
Katsuki remembered a certain plushie he saw last time, that he really wanted. With this in mind, he agreed.
“Fine.”
“That’s a good boy, now come here.” Izuku patted the bed.
Katsuki laid down on the bed and let Izuku pull off his pants and boxers. Katsuki was still mad, and wasn’t giving in to the tickles and kisses Izuku was trying to give him.
“Cmon Kacchan, it’s not so bad.” Izuku said as he patted Katsuki’s now diapered bottom.
“Like you would know.” Katsuki reminded, pouting again.
“I guess you’re right.” Izuku laughed.
He pulled Katsuki’s pants back up, then gave him a kiss on the lips. Katsuki tried to turn his head away, but Izuku was too fast.
“Okay since you behaved, we can go now.”
Katsuki jumped up from the bed. “Finally! Let’s go.” He raced out of the room and to the front door, hastily putting his shoes and coat on. In his excitement to finally be going, he forgot to use the bathroom before he left.
Izuku followed, making sure that they both weren’t forgetting something. He checked that he had his wallet, because of course he was going to need that. When he was sure he was ready to go, he walked out of the house, locking it behind him. Katsuki was already in the passenger seat of the car, waiting impatiently.
____
Katsuki practically ran to the door of the toy store, while Izuku had barely even made it out of the car.
“Kacchan! You have to wait for me!”
“No I don’t!” Katsuki yelled back.
He walked through the automatic door and was greeted by an employee.
“Anything I can help you with today sir?” The woman asked.
Katsuki blushed. “No, just looking.” He shyly replied, avoiding her gaze.
He walked through the aisles, not even waiting for Izuku to join him. It would probably make Izuku mad, but Katsuki thought he kinda deserved it after making him be good all week and then making him wear a diaper to the store.
He looked at all the cars, action figures and superhero stuff first. He took a picture of a couple that he was interested in to put on his wishlist for later. But he already knew what he planned to get today.
As he walked to the plushie section of the store, he could feel that he kinda had to pee. He grimaced, of course he forgot to use the bathroom before he left. He could probably hold it until they got home though. Then another thought popped into his head, distracting him.
Wait! What if the plushie he wanted wasn’t here anymore? What if someone bought him already? His smile slipped a bit as he anxiously made it closer to the shelves. He scanned them quickly, looking for the pale green fabric that he remembered it being.
His heart dropped when he didn’t see it. That wouldn’t stop him from looking further though. He pushed the plushies aside, looking behind them, seeing if he might’ve been hiding. The search made him giddy again, and he starting murmuring to himself.
“No, not you. No, but you’re cute. Ooo! I didn’t see you last time.”
He placed a lion plushie on the ground, this would be his backup in case he didn’t find the one he wanted. He went on to search the last shelf, not even realizing that someone was walking towards him.
Izuku walked up to Katsuki, watching him search though the plushie shelf. He knew Katsuki was probably going to be here, but he allowed Katsuki a little freedom while he got a cart and looked around a bit himself. He saw there was a plushie already picked out.
“Kacchan, how many do you plan to get?” Izuku asked him, light heartedly.
Katsuki jumped a bit and then turned to look. “Um...I don’t know...”
Izuku just rolled his eyes and motioned for him to keep looking.
Katsuki almost gave up on his search, when he spotted some light green fur peeking behind a large unicorn plush. He reached behind and grabbed it. His eyes lit up as he saw the green dragon’s face look up at him. There he was! The one he wanted!
He cuddled him quickly to his chest, not wanting to let go of him after his long search. He turned to Izuku, who was looking at some of the plushies too.
“Okay, I’m done shopping.”
“Oh, but look how cute this little hippo is Kacchan!” Izuku picked up a purple hippo and showed it to him.
“No, I don’t want a hippo. I got a dragon.” He hugged the dragon closer.
“A dragon?” Izuku looked down at the green dragon he was holding.
“Can I see? He looks so cute!” Izuku asked as he reached out for the dragon.
Katsuki reluctantly handed him to Izuku. Izuku held the dragon up and pet the soft green fabric.
“Aww he’s perfect. What’re you going to name him?”
“I don’t know. Can we go pay now?”
Katsuki knew he was starting to be bratty, but he had to pee a lot more now. The constant moving from looking for his dragon made the urge even stronger. He just wanted to take his dragon and go home. He bent down and grabbed the lion, planning to put it back on the shelf. He made a low groan as his bladder protested against the movement.
Izuku raised his eyebrows at the sound. “You okay baby?”
“Yes. Can we go?” Katsuki said, walking down the aisle, the dragon still in his hands. He was walking a bit stiffly though.
Then it dawned on Izuku. He pushed the cart and caught up to Katsuki.
“Kacchan...do you have to pee?”
“No.” Katsuki quickly responded, looking at his dragon and avoiding Izuku’s gaze.
“Baby, don’t lie to me.” Izuku grabbed Katsuki’s arm, making him stop walking.
“Fine, I do. Just a bit though.” He confessed as he quickly darted his red eyes up to look at Izuku.
“Well I put a diaper on you for a reason Kacchan.”
Katsuki’s eyes widened. Did Izuku want him to piss himself in the store? Where everyone could see?
“It’s okay baby, no one is even here.”
“But...” Katsuki was now looking at the ground again, shuffling his feet nervously.
Izuku wrapped his arms around Katsuki, pulling him close. Katsuki’s head was on Izuku’s shoulder, and the dragon was still being held. It looked like they were hugging, but Izuku snaked his hand down to Katsuki’s crotch, rubbing it lightly. Katsuki whined, trying to pull back.
“Shhh...it’s okay Kacchan.”
“No, it’s embarrassing.” Katsuki mumbled.
He really had to pee now and Izuku’s hand on him wasn’t helping. Izuku knew this and kept rubbing against the front of his pants, feeling the diaper crinkle underneath. Izuku looked both ways around the aisle, making sure the coast was clear.
“No ones around baby, you can let go.”
Katsuki cuddled his dragon tighter to his chest, letting it calm him down. He didn’t answer Izuku.
“Daddy’s here baby, I got you.” Izuku told him in a soft tone.
“Promise no one will see?” Katsuki whispered, his voice sounding more like when he’s little.
“Promise.”
Izuku whispered praises into his ear and rubbed the front of his diaper softly, pressing a bit more. He heard Katsuki sigh and then could feel some piss flooding the inside of the diaper.
“You’re such a good boy Kacchan.” Izuku cooed.
Katsuki’s eyes were closed, but his fingers were brushing against the soft fur of the dragon, soothing himself. He could feel himself slipping into his little space as he pissed himself. Izuku’s voice in his ear dragging him even deeper.
Izuku could feel Katsuki stop peeing and he gave Katsuki’s front one more pat. He rubbed Katsuki’s back and let Katsuki relax for a minute, knowing that he might be fighting against his instinct to fall into little space.
“Daddy?” Katsuki’s small voice spoke up.
“Yes baby?” Izuku assumed Katsuki let himself slip into it, knowing that Izuku would take care of him.
“I’m done now.”
Izuku chuckled. “Okay, wanna go now?”
“Ya...can I get the dragon?”
Izuku pulled away from Katsuki, but held his hand as they walked to the cash registers.
“Of course you can baby, you’ve been such a good boy for me today and all week.”
Katsuki smiled widely, pink dotting his cheeks as he held the dragon, not putting it into the cart with the other stuff. He didn’t even realize earlier that Izuku had got some hero merch for them both, and he was too focused on the pale green dragon to even check it out.
He reluctantly let it go for the employee to ring up and as soon as it was placed in a bag, he snatched it up. Izuku smiled apologetically at the employee. Katsuki’s quick attachment to the dragon made his heart so full, so he let him keep hanging on to it. He paid for the stuff as Katsuki stood there in his own little world, petting the dragon.
He grabbed Katsuki’s hand, leading him out of the store. Katsuki lifted the dragon into the air, pretending the plushie was flying. He made swishing noises to imitate the sound of its wings.
“Cmon Kacchan, you can play when we get home.” Izuku pulled him along to the car, giggling as Katsuki still continued to make the dragon “fly”.
“Okay Daddy!” He let Izuku strap him into the passenger side of the car.
Katsuki played with his dragon as Izuku started the car, but then noticed how his diaper was wet.
“Daddy, I feel icky.”
“I know baby, I’ll change you when we’re home.” Izuku assured.
Katsuki nodded and went right back to playing with his dragon, holding it up to the car window, making it look like it was flying while the car was moving. Izuku smiled at his baby boy, seeing him play always warmed his heart.
They’d been so busy lately that they hadn’t visited the toy store in awhile. Izuku would have to make a point to take Katsuki more since it made the blonde so happy. If that also meant having to get a larger shelf for Katsuki’s plushies, then so be it.
Also, Izuku would have to remember to always put a diaper on Katsuki before they went out, no matter how much the blonde protested.