Author's Notes: I've been itching to write infantilism for quite a while, and finally, I decided to do it. What started as just an idea to write a fic turned into building an entire verse in my head that I didn't want to confine to just one fic, even if that fic amounted to several thousand words in the long run. So, rather than poke at this for ages upon ages until I was satisfied that every single detail of every thing I wanted to explore was absolutely perfect, I've made the decision to break the tale I saw in my head into several short fics (and possibly more, as prompt tables or drabble comms inspire) that all happen within a single universe. This is the first of them, and the story that starts it all.

Disclaimer: I do not own any part of Harry Potter, and make no money from playing in their sandbox for the purposes of this fic.

Lots of love to lorcalon for the beta, yet again.

"I think we're all done down here. Break for lunch?"

Neville stretched his arms and twisted to glance at the clock over the mantel in their sitting room. They had started cleaning the house just after breakfast, and somehow, more than four hours later, had only finished the lower floors. "Lunch sounds brilliant. What were you thinking?"

"The usual?" Harry suggested with a small grin. Laughing, Neville shook his head as he dropped his arms.

"All right, how about you go pick up the take-away, and I'll get a jump on the bedroom then? At least that way, we might finish all this a bit sooner." Harry nodded, and Neville leaned in towards him to give him a brief kiss. "Hurry back."

"I will," Harry said, before he drew out his wand and Apparated.

Neville took a few moments to survey the lower floors of Grimmauld Place again, ensuring that everything was as clean as they could make it. When he was satisfied with the job he and Harry had done, he made his way upstairs and paused briefly at the top of the stairs to consider the doors along the hall.

Their bedroom, at the end seemed like it would be the quickest one to clean. With the promise of good food on the way, Neville decided to start there, in hopes of knocking that room off their list entirely before he and Harry sat down to eat. Determined, he made his way into their room and began sorting through their bedside stands.

His first thought, when he found the thick magazine tucked away in Harry's bedside drawer, was that Hermione had left it behind by accident the last time she'd been over. That Harry would tuck it in his nightstand, rather than return it straight away, was still a little strange, but at first glance, it was the simplest explanation. But Hermione hadn't visited Grimmauld Place in over a month, and when Neville started to set it aside in the 'do not Vanish' pile, he glanced down at the front cover of the baby catalogue and spied the date of the issue.

Curious, Neville perched himself on the edge of the bed and laid the catalogue open beside him, flipping through its pages to find several of them had been dog-eared. Pausing at one of the pages, he noticed a few items had been circled, with notes in Harry's distinctive scrawl squeezed along the margins. Neville frowned as he looked closer at the things Harry had circled and noticed that they were all distinctly boys' things. With Teddy already much too old for anything in the catalogue, and Hermione and Ron expecting a girl, there was no reason that came to mind to explain why Harry seemed to have been picking out toys for a baby boy.

"Neville, are you in he-"

Neville looked up from the catalogue to find Harry standing frozen in the doorway of their bedroom. His eyes were wide and focussed on the open catalogue with an expression of fear. He was breathing rapidly, and didn't seem to notice Neville stand until he was beside him, laying a hand on Harry's shoulder. Harry's attention snapped to Neville, and the fear in his eyes was mixed with something else that Neville was unable to place.

"What's wrong, Harry?" Neville asked, sliding his hand over Harry's shoulder in an attempt to soothe him. Instead, Harry's eyes flickered again towards the catalogue as he refused to meet Neville's gaze.

"Nothing."

"You're shaking." Bringing his other hand up to lightly grasp Harry's chin, Neville turned him to face him, although Harry still kept his eyes aimed away from Neville. "Talk to me," he urged, but Harry only shook his head. "Is this something to do with the catalogue?"

Harry tensed and took a step away from him. "Neville, don't."

"Listen, if this is something about you wanting a family-"

"Neville-"

"We can do that, Harry, really. There are options for us-"

"That isn't it!" Harry snapped, silencing Neville with his desperate tone. He wrapped his arms around himself as he turned his face away again, staring resolutely at the wall as he continued, "It isn't anything like that. It's just..." Harry hesitated, and Neville saw his lower lip begin to tremble before he took a deep breath to steady himself. "Throw it away, all right? Forget about it. Please."

Neville shook his head and took a step closer to Harry, reaching for him and then dropping his hand when Harry retreated back from him. "Tell me what this is about, Harry. You wouldn't be so wound up about me finding that, if this wasn't something important to you."

"You'd leave... if I told you..."

Stepping towards Harry again, Neville pulled the other man into his arms before Harry could pull away a second time, and was relieved when Harry didn't struggle. Neville wrapped one arm around Harry's waist to hold him close while the other tucked beneath his chin, tipping his face up until Harry reluctantly met his eyes. "It's been four years now, love, and it's never once crossed my mind to leave you; I'm not going anywhere."

"This is different, Nev," Harry protested. "This isn't... normal."

Neville cracked a small smile and dipped his head to rest his forehead against Harry's. "Since when have we ever been 'normal'?" Harry whimpered and Neville tightened his arm around him. "You can tell me anything, you know that. If this isn't about you wanting a family, then what is it about?"

Harry's hands came up to curl around the front of Neville's shirt, and he moved to bury his face against Neville's neck. He was silent for several moments, and Neville began to think he wasn't going to speak, before he finally whispered, "It's... something that I want, Neville."

Neville considered Harry's answer in silence, stroking his hand over the small of the other man's back. "I think you need to be more specific, Harry... What do you want?"

"Those things," Harry whispered in a desperate tone. "I want to have those things..."

Never stopping the movement of his hand over Harry's back, Neville turned the explanation over in his mind for a moment. In the catalogue, Harry had marked everything from toys to dummies, and the few clothing items that had been marked had included scribbled notes about sizes that Neville hadn't understood at first glance. Now, though, it began to come together, and he moved his arms up higher on Harry's back to hug the other man against his chest.

"I'm sorry," Harry murmured, clutching tighter at Neville's shirt. "I know it's weird, I just-"

"Hush." Neville pressed a kiss against Harry's temple. "This isn't weird, love. It's okay. I just want you to tell me exactly what it is you want, all right?"

Harry pulled back to look at him with wide eyes, and Neville brushed at a wayward tear that slipped down his cheek. "You... aren't disgusted by me?" he asked in a whisper. The relief and amazement in his tone pulled at Neville, and he leaned in to brush a brief kiss against Harry's lips.

"Never. But if this is something you want me to give you, Harry, you have to tell me about it."

Harry's breath caught at Neville's words, and his eyes widened further before he threw his arms around Neville's neck and clung to him. "You would really...?"

Neville nodded, nuzzling his cheek against Harry's. "I can't promise that I can do everything you want, because I don't know exactly what that is yet. But I do promise that I'll try."

The children's shop tucked away in Diagon Alley wasn't crowded when Neville stepped inside, and he sighed in relief. Despite his reason for coming in, he felt comfortable inside the store, but had not been looking forward to trying to navigate the unfamiliar store through a crowd of shoppers and their children.

Looking around at the shelves he passed, he ran through the short list of items in his head that he could recall from his conversation with Harry and the catalogue he'd seen. Harry had remained vague about his interests, despite Neville's assertion that it was all right to tell him, and Neville hoped that his surprise would help Harry realize he was sincere. Navigating his way towards the toys first, Neville found himself at the back of the store, staring at a large section of shelves against the wall that were filled with soft toys of varying sizes.

Neville hesitated as he scanned the array of animals on the shelves, trying to think back to the night he'd found the catalogue, when Harry had let go a little, while they stretched out on the sofa to talk. He'd gotten a brief glimpse of that side of Harry, before the other man had reined himself in again, and Neville frowned at the toys in front of him as he wondered what seemed to fit Harry's preferences. For several minutes, he browsed the shelves, plucking a few toys up to examine them closer before ultimately replacing them.

A grey elephant caught his attention, and when Neville stroked his hand over it, he found it softer than he'd expected. Smiling, he started to pick up the elephant, but hesitated as he took notice of something tan on the shelf below it. Crouching down, Neville found himself face-to-face with a fairly large stuffed lion cub and grinned.

He picked it up off the shelf and gave the toy a squeeze, laughing when it let out a tiny roar that sounded much more like a kitten's meow than anything ferocious. A feeling of warmth washed over him as he imagined Harry holding the animal, and he straightened, tucking the lion cub under one arm.

Neville spent just under an hour continuing to browse the shop before he took his purchases to the till. The witch behind the register smiled and made small talk with him while he paid and she gift-wrapped the lion for him. When he finally stepped out of the shop and back out into Diagon Alley, with his purchases shrunk and tucked away into a pocket of his robes, it was just past four and left him only half an hour before Harry would make it home.

Once home, Neville tucked away his purchases, save the lion, which he set on the floor beside one arm of the sofa in the sitting room, where Harry wasn't likely to notice it until he was ready to pull it out. He settled himself at that same end of the sofa just as the fireplace flared to life, and Harry stepped through in a swirl of green flames. Harry smiled while he pulled off his robes and tossed them over the nearby chair.

"I wasn't sure you'd be in already. Made an early day of it?" he asked as he slipped beside Neville on the sofa. Neville's arm closed around Harry's waist and hugged him closer.

"Had some things I needed to do in Diagon. I actually just got in." Tipping his cheek to rest atop Harry's head, Neville nuzzled his hair. "How was work?"

Harry sighed and pressed himself closer into Neville's embrace. "Tiring."

"Need to let go tonight?" Neville asked softly. Harry's unsteady intake of breath was evidence he understood the meaning of the question, and he gave a hesitant nod.

"That would... be nice..."

Neville smiled as he straightened to lean over the arm of the sofa. "In that case, I got you something today."

"You did?" When Neville turned towards Harry with the wrapped present in his hands, Harry's eyes were wide and uncertain. "What... what is it?"

Smiling, Neville passed Harry the gift. "Open it and see."

Harry hesitated, but Neville's confident smile seemed to encourage him and he tore into the paper. Neville heard his breath hitch as the wrappings fell away to reveal the stuffed animal, and Harry's hands trembled as he reached out to touch it. His breathing sped up when his fingers brushed against the soft fur of the lion, stroking along the top of its head.

"You... bought this for me?" Harry whispered, raising his gaze to Neville with an expression of awe. "It's really mine?"

Neville leaned in to press a light kiss to the fringe of Harry's hair. "Of course it's yours. I don't see any other little boys here it could be for, do you?" A faint blush suffused Harry's cheeks at the question, and he pulled the toy into his arms, wrapping them tightly around it. When the lion let out its kittenish roar, a sheen of tears welled at the corners of Harry's eyes as he smiled and buried his face against its head.

"Thank you."

Harry's words came out muffled, and Neville brushed the discarded wrapping paper to the floor as he reached out and pulled Harry into his lap. Immediately, Harry curled against his chest, his arms still clinging to the new toy. Neville settled his own arms around Harry's waist to cuddle him close, resting his cheek on top of Harry's head. Harry squeezed the lion again, drawing a soft chuckle from Neville when he mimicked its roar. Sliding one hand up Harry's back, Neville brought it to the back of his head to stroke his hair. He noticed Harry's hand trembled slightly as he turned the toy towards Neville's chest and made a soft growling sound before pressing its face against his shirt and then withdrawing. When Harry brought the toy in for another attack, Neville smiled down at him.

"Should I be worried that your lion is trying to eat me?"

"'s playing," Harry murmured. He tipped the toy up slightly, so that the next attack pressed the lion's face against Neville's neck, and made a kissing noise. "Think he likes you... Daddy." Neville met Harry's gaze as he looked up through his lashes, the uncertainty in his expression making Neville tighten his other arm around his waist.

"Well, Daddy likes him, too." Dipping his head, Neville pressed a kiss against Harry's forehead. "And Daddy loves you, Harry," he murmured.

Harry's expression crumpled at the words, and he clutched at Neville's shirt, crushing his toy between them as he pressed in to bury his face against Neville's neck. "Thank you," he whimpered, his voice muffled by Neville's neck. Smoothing his hand over Harry's back to calm him, Neville shushed him and began to rock Harry gently when he felt tears against his skin.

"I'm sorry," Harry said through his tears, receiving a tight squeeze from Neville when his voice cracked. "I don't mean to-"

"Hush," Neville murmured, silencing Harry. He continued to sooth Harry until the other man had ceased to tremble in his arms and there was no new wave of wetness against his flesh whenever Harry turned his head. Without withdrawing his arms from around Harry, Neville turned them until his back was pressed against the arm of the sofa and his legs laid out along the cushions. Harry settled more comfortably in his lap, dangling his legs over the edge of the sofa while he curled against Neville's chest.

"All better?"

Harry nodded. "Thank you, Daddy," he whispered shyly.

Leaning in, Neville pressed a kiss to Harry's forehead and offered him a smile. "Anything for you, Harry."