A/N: Because, hey, if I wrote about pregnant Bucky and Tony I also need to write about the babies/children.

Disclaimer: So, the kids are my own original characters, but nothing else is.

Steve had just started to drift to sleep when a loud crash brought him instantly to full wakefulness. He jerked upright, ready to take on any threat.

But there was no danger. Just a startled toddler sitting in the middle of a collapsed block castle.

He looked up at Steve with wide brown eyes. "Uh-oh."

"Uh-oh," Steve agreed. He crouched down beside the boy. "Are you okay, Matty?"

Matthew nodded and pushed at the surviving chunk of wall, toppling it over in another loud crash. "Boom," he said.

Steve plastered on a smile. The older boys were going to be upset to find their castle destroyed, but Matthew wouldn't understand. "The castle went boom? Oh no, where are the king and queen going to live now?"

Matthew looked down at the block clutched in his hand and back up at Steve. "Oops."

"I'll help you fix it," Steve said.

"No." Matthew protectively cradled the block against his chest. "Mine."

"Okay," Steve said. "You can do that part. I'll start on the rest."

He started rebuilding the castle as Matthew happily banged a few blocks together. Daniel and Alexander had spent the better part of the morning arguing over the design, building and rebuilding the castle until they were finally satisfied. Steve doubted he could remake it exactly the way it was, but he could try, least.

Steve smoothed down Matthew's sandy blonde hair. "You were supposed to take a nap."

"No."

"Yes," Steve said. "You were supposed to stop causing trouble for a few minutes so Daddy could take a nap, too."

"No."

"That's not very nice. Think of your poor suffering father." He poked Matthew in the side and the toddler giggled and squirmed away from him.

"Eat."

"But you just had lunch," Steve said. He glanced at his watch. Huh. It was later than he thought. "Never mind." He stood and stretched. "You ready for a snack, Matty?"

Matthew stood on his tiptoes, his arms outstretched. "Up."

Steve scooped him up and settled him on one hip. "Okay, let's see what we can find in the kitchen."

He had expected the kitchen to be empty, but Tony and Daniel were sitting cross-legged on the kitchen floor with what looked like Tony's entire screwdriver collection spread out around them.

Steve stepped carefully over the mess. "What's all this about?"

Tony held up the communal toaster. "Daniel's going to take this baby apart in less than two minutes. Isn't that right, kiddo?"

Daniel nodded, his blue eyes steely with determination.

"Jarvis, two minutes on the clock, please. And ready, set, go!"

Daniel snatched up the nearest screwdriver and went to work, his small hands flying over the metal surface. The outer shell came off quickly and then he began separating all the delicate innards into piles of wires, springs, and circuit board. Steve barely had time to marvel at all the components that went into a toaster before Daniel triumphantly tossed the screwdriver down.

"Time," Tony announced. "Jarvis, how'd he do?"

"One minute thirty seconds, sir."

"Alright, Daniel! High five."

Daniel grinned. "Beat my record by twenty seconds."

Tony ruffled his hair. "You are getting so good at this. I think you're even faster than I was at your age."

"Actually, sir-"

"Quiet, Jarvis. Can't you see we're having a moment here?" Tony sighed dramatically. "We were in the middle of the best mother-son bonding moment in the universe and you just had to interrupt."

Daniel and Steve exchanged a look of fond exasperation.

So maybe Daniel shared Tony's engineering genius. And maybe he looked almost exactly like a miniature Tony all the way down to his grease-stained t-shirt and jeans. He just didn't have Tony's larger than life personality. And Steve was grateful for that. As much as he loved the man, the world wasn't ready for another Tony.

"It's okay," Daniel said. "We can bond all the time." He squinted up at the ceiling. "Thanks for timing me, Jarvis."

"It has been my pleasure," Jarvis said warmly. "Sir and I look forward to your continued successes."

"You said it, J," Tony said cheerfully. "And I'm sure Matthew's proud of his big brother, too. Aren't you, Matty?" He scooped the toddler up in his arms and spun him around in a circle. "But you didn't just come to see Daniel, did you?"

"Food," Matthew said.

"Oh, of course. Let's make-no, why don't I find you a banana? Bananas are safer. Mommy doesn't have to cook anything. Remember when Mommy's pudding exploded?"

"Boom!" Matthew said, clapping his hands together.

Steve sighed. There was definitely a reason "boom" had been one of the first words Matthew learned.

Tony settled Matthew at the kitchen table with a bowl of bite-sized banana chunks and returned to lean against the counter next to Steve. "So, next time there's a problem with the toaster, Daniel can take it apart and check it out. Awesome, right?"

"It's great," Steve agreed. "Now you just have to teach him how to put it back together."

"Oh, he knows that part already," Tony said proudly. "You have to know how something's put together before you can break it down and rebuild it into something better."

"Our toaster doesn't need an upgrade. It's fine just the way it is." He frowned at the pile of parts. "Was."

Tony sighed heavily. "Let's get to work, Danny boy. Your father hasn't learned not to panic when he sees parts on the floor."

"I'm not panicking," Steve said. "But somebody else will when they can't eat any waffles tomorrow."

Tony's eyes widened. "Faster, Daniel, faster!"

Daniel just rolled his eyes and continued methodically reattaching the parts together.

Tony leaned his head against Steve's shoulder. "Our boy's growing up so fast. Today, a toaster. Tomorrow an oil tanker."

Steve wrinkled his nose. "An oil tanker?"

"Right, nothing but bad memories there. Never mind." Tony frowned thoughtfully. "Maybe Bucky-"

Bucky's voice floated down from the hallway. "Alexander. Alexander Barnes-Rogers, you bring that back right now."

"Incoming," Tony said. "In 5, 4, 3, 2, 1."

"Whoosh." Alexander raced past them, arms outstretched with a small metallic object clutched in his fist."

Steve let him make a pass around the kitchen and then snagged him under his arm as he headed into the living room.

"Dad," Alexander complained. "You're going to crash my plane."

"Crashing planes is my specialty."

Tony snickered as Alexander looked at him blankly.

"Never mind," Steve said. "You'll understand when you're older." He held out his hand. "Let me see what you have."

Alexander clutched his hand to his chest. "It's not Mom's."

"I don't care. Let me see it."

Alexander sighed heavily. "Fine, take it."

Steve looked at the item in his hand. "A pocket knife? You know you're not supposed to play with sharp objects."

Alexander crossed his arms over his chest. "Daniel gets to play with them. Why can't I?"

Steve glanced down as Daniel began carefully setting the screwdrivers back in Tony's tool box. "Because your brother is using them as tools, not toys. You understand the difference, don't you?"

Alexander heaved a sigh. "I guess."

"And you do not run with knives. Ever. Do you hear me?"

"Yes," Alexander said sulkily.

Bucky appeared in the kitchen, wild-eyed and disheveled. Steve felt sorry for the effort it had taken for a hugely pregnant Bucky to chase after his child, but he also felt a bit sorry for Alexander seeing the murder in Bucky's eyes.

"Alright, where'd my little brat get off to?" Bucky demanded.

Alexander cringed and ducked behind Steve.

"Alexander Barnes-Rogers," Bucky said. "You aren't getting out of this. When I told you we were having a knife safety lesson, you don't go running off down the hall-"

Tony gently pushed Bucky backwards, guiding him towards the plush armchair in the living room. "Deep breaths, deep breaths," he said.

"I'm not through with you, young man," Bucky said sternly. "We're going to have another long safety talk. And you're going to be in big, big trouble if you try running off again."

"Don't worry, darling," Tony said soothingly. "Steve will take care of it." He stroked Bucky's hair. "You just relax and let me take care of you."

Bucky sagged back into the chair and sighed contentedly. "You're so good to me."

"And you're so good to me," Tony said. He kissed Bucky's neck and rubbed his shoulders. "Look at this beautiful body I get to worship."

Steve smiled ruefully. As an alpha, he was supposed to be thrilled when his omega lover got pregnant. And he was. Of course he was. But he was pretty sure Tony was far more excited about Bucky's pregnancy than he was.

"Sir," Jarvis said. "I am detecting-"

And that was all the notice they had before Loki appeared in a swirl of green smoke.

Alexander jumped up and down, his face lit up with excitement. "Yay, Loki's back."

Bucky pushed Tony away. "What are you doing here? Emma's not supposed to be born for another month yet."

"Oh, I was just blowing up a few buildings in the area and thought I'd stop by." Loki made a show of inspecting his fingernails.

"So, this is just a courtesy call to let us know explosions are happening later."

Loki smirked. "Something like that. I do remember our arrangement."

Matthew tugged at the hem of Loki's tunic. "Up," he said.

Loki frowned. "Tell this little pest that I'm not going to hold him."

Tony smirked. "Tell him yourself."

Loki bent down to look the boy in the eye. "I'm not going to hold you. Absolutely not."

"Yes," Matthew said.

Loki drew himself back up to his full height. "Such impudence at such a young age. But you are a Stark. I suppose you can't help yourself."

"Up," Matthew repeated.

Loki held his hands out. "Look, brat. These hands weren't made for holding children." His eyes twinkled. "But they were made for mischief." With a flick of his hand, Matthew started hovering four feet above the floor.

Matthew screamed with delight and clapped his hands. "More, more!"

Loki raised a hand and Matthew started circling overhead. "Little daredevil," Loki said fondly. "Just like your mother."

"Mommy, Mommy!" Matthew called. "Look."

Tony halfheartedly reached upwards. "Oh, yes. You're so high up now. I can't even reach you. I guess you'll have to turn into a bird and live in the ceiling."

Matthew giggled and grabbed at Tony's hands. "B'loon."

"You're not a balloon. You don't have a string." He tugged at Matthew's foot. "Is this a string?"

"No," Matthew shrieked as Tony started tickling the bottom of his foot.

"And we all know what happens to balloons that run out of air," Loki said. He crooked a finger and Matthew flew around the room, squealing with joy as he veered around everyone in the kitchen and then rocketed out into the living room.

"No fair," said Alexander. "I want to try that."

"Be careful what you wish for," Loki said. He raised his other palm towards the ceiling and lifted Alexander off the ground.

"Yes!" Alexander said. "Daniel, you have to try this."

"Okay," Daniel said uncertainly. He reached for Alexander's hand.

"Prepare yourselves," Loki intoned solemnly. He moved his hands in a juggling motion and the children circled around Loki's head for a moment and then dropped down neatly onto the couch.

"Again, again," Matthew said.

Loki snorted. "I'm not going to spend all day tossing you in the air. I'm a busy man, you know. And I'm sure you have obligations of your own."

"That's right," Tony said. "We're going to play in the park with Uncle Thor, Uncle Bruce-"

"Tashi," Matthew added.

"No, sweetheart. Tasha and Clint are still on their mission."

"Loki can come instead," Alexander said hopefully.

"I'm not exactly welcome in public," Loki said in a low voice. He met Tony's eyes, a wry twist to his mouth. "Especially around children. What's to say that they won't spontaneously turn into beasts just by being in my presence?"

"Hey, no," Tony said indignantly. "Nobody here thinks that. They don't even know you're an omega."

Loki looked away. "Small mercies, I suppose."

"Nope, nope, nope. I don't want to hear any more moping from you. You're going to take the kids out, have a great time together, and forget all about what everyone else thinks."

Loki blinked. "You would trust me alone with your children? Are you mad?"

Tony elbowed Loki in the side. "Oh, don't look so shocked. You know and I know they're not going to turn into snakes just because you touch them. They'll be fine."

"But, but think of all the other ways I could endanger them," Loki spluttered. "I could even kidnap them and keep them as my own."

"Nah," Tony said. "If you were going to take them, you would have done so already. But you're too smart for that. It's so much easier to play with them for a few hours and hand them back to Mommy when they start whining." He pressed Matthew into Loki's arms. "And Thor and Bruce will be happy to come with you if you need any help."

"If you're absolutely sure," Loki said, still looking a little bewildered.

"We're sure," Bucky said. "Take them. Please."

Loki grinned widely and then he and the children vanished in a burst of glitter.

"Hooray, we have the whole place to ourselves." Tony draped himself across the back of Bucky's chair. "You wanna watch some porn?"

Bucky snorted. "You don't own any porn, idiot. It's all been replaced with romantic comedies and cartoons."

"Lie," Tony said. "All lies. Steve, will you be a dear and fetch Magic Mike from under the bed?"

Bucky let out a bark of laughter. "That is not porn."

"Yes, it is. It's got strippers in it."

"Still not porn."

"And I suppose you'd classify it as a romantic comedy then?"

Steve could already see the argument descending into pinching and tickling. He sighed heavily. "I'll go get the movie. You can settle this after we watch it."

When he returned, Bucky and Tony were curled up together in the chair, fast asleep. Steve just shook his head and draped a blanket over them.

He hadn't really been in the mood for Magic Mike anyway. Tony and Bucky thought the movie was hilarious and they usually giggled like children through the whole thing, but Steve had never really gotten into it. It just wasn't his taste, he supposed. He'd rather watch an actual comedy. But while his lovers were sleeping, he'd settle for a good spy novel.

Steve was halfway through his book when Loki and the children reappeared in a burst of flame.

Tony yelped and tumbled gracelessly onto the carpet. "Are you trying to give me a heart attack? Warn a guy next time."

"My apologies," Loki said, not looking the least bit apologetic.

Alexander climbed onto Bucky's lap. "It was awesome. We saw some rabbits and a bird nest and then we climbed a tree and played on the swings and Loki bought us ice cream."

Bucky patted his head. "Sounds like you had fun."

"And oh yeah, Daniel found some cool rocks. Loki said we could figure out what they are in the lab."

Daniel held out a handful of pale colored stones.

Tony perked up. "Oh yeah. I have a book down in the lab. Let's take a look."

"After dinner," Steve said. "I'm sure the kids are starving after all the excitement. Loki, do you want to stay for dinner?"

"I'm afraid I already have plans." Loki said. "Tomorrow at noon, I'm turning the subway into a giant python. I have a great deal of preparations to make for that."

"Uh, thanks for the warning," Steve said. "Jarvis?"

"Noted. The Avengers will be summoned to arrive on scene precisely at noon."

"Fantastic," Loki said. "Until tomorrow." He vanished.

"Huh," Tony said. "A python. That's a new one."

Bucky shrugged. "We've seen worse. Now, what's for dinner? I'm hungrier than the kids."

As the only one who could manage to follow simple recipes without causing an explosion or setting things on fire, it usually fell to Steve to make dinner. Bucky and Tony were responsible for clean-up.

Since it was getting late and everyone was already hungry, Steve pulled out a couple boxes of macaroni and cheese. For some reason, his little family all loved macaroni and cheese. Bucky could eat two whole boxes on his own. And even Tony, who usually ate like a bird, could be convinced to sit down at the table to eat a whole plate.

Steve loved when everyone sat down for a meal together. With their busy schedules, it wasn't always possible, but he made as much time for family as he could. He watched Daniel and Alexander have an animated discussion about the rocks they found at the park and Bucky and Tony affectionately leaning against each other and he felt a surge of pride. This was his family.

Tony whispered something into Bucky's ear and Bucky did a spit take. "God, Tony," Bucky spluttered. "You can't tell me these things during dinner."

Steve rolled his eyes. "You two are setting such a wonderful example for the children." He looked sternly at Alexander and Daniel who were giggling behind their hands. "Don't grow up to like your mothers," he said. "They've never managed to grow up."

"I am grown up," Tony protested. "Very, very grown up." He stuck out his tongue.

Matthew burst into a fit of giggles.

"Yes, Mommy's being very silly," Steve said.

But that was normal. Tony was a fun parent and the kids adored him. And Steve would rather have Tony's style of parenting than the cold, distant relationship Howard and Tony had.

After dinner, it was Tony's turn to do the dishes while Bucky herded the children into the bath. Steve went down to the gym for an hour, took a quick shower, and crawled into bed to read the rest of his novel.

As he finished the last page, the bed dipped and Tony's arms wrapped around him. "How's my favorite sexy supersoldier?"

Steve smiled and stroked Tony's hair. "Tired. Ready for bed. Where's Bucky?"

Tony grinned. "Reading to the kids. Or more likely, falling asleep reading to the kids."

"Probably," Steve agreed. Bucky was sleeping a lot more now. Being pregnant was wearing him out. But at least Bucky had remained in relatively good spirits throughout. It probably helped a lot that Tony was eager to fuss over him.

Tony nuzzled into Steve's side. "We are so domestic," he said. "Warms my heart."

"You've been awfully cuddly today," Steve said.

"Have I?"

Steve eyed him suspiciously. "What do you want, Tony?"

Tony fluttered his eyelashes. "Nothing. Nothing except your body."

Realization dawned. "Your heat's coming," Steve said. He could barely smell the heat-scent now and already his body was responding. He was going to have a hell of a time getting any sleep.

"Ah," Tony said. "That must be why I offered to suck Bucky under the table."

Steve shook his head. "Oh, Tony." It was sad that he knew the signs better than Tony did.

Tony rolled onto his back, stretching luxuriously. "I can't wait for my heat to kick in. Then we can have delicious, glorious sexytimes."

Steve rose with a sigh. "Take your birth control now," he advised. "I know you're not going to be in any condition to remember later."

Tony watched him warily. "Where are you going?"

"To get Bucky. He's going to be pissed if we leave him out."

Bucky was fast asleep, just as Tony had predicted. He had pulled a chair up beside the bed to read to the kids and somewhere along the way he had slumped forward onto the bed, faceplanting onto the book. Well, at least the kids were all asleep, too.

Steve gently scooped Bucky into his arms, careful to make as little noise as possible.

"Hey, Steve," Bucky murmured sleepily. "I don't think I finished the story."

"That's alright," Steve said. "It did its job anyway."

He deposited Bucky onto the bed beside Tony.

Bucky stirred and licked his lips. "Mm, Tony. You smell all sorts of fuckable."

"Hey," Tony said. "You better not be teaching my baby that kind of language."

Steve snorted, remembering how horrified Bucky had been when a three-year-old Alexander told him to fuck off.

"Your baby's down the hall. He's not going to hear a damn thing." Bucky leaned closer into Tony's space and ran a finger over his jawline. "I'll make sure to keep your mouth busy, just in case."

Tony groaned and his eyes fluttered shut. "Sounds good to me."

With a little nudge from Bucky, Tony tumbled over sideways onto the bed and the two omegas started passionately making out and grinding against each other. Steve settled back into his pillow for a moment. Soon enough they'd be whining for him to help them out, but for now he was content to watch. After all, there was nothing he liked better than seeing the two of them happy together.

He was contemplating joining them when there was a knock on the door. "Dad?"

Bucky sighed. "Go back to bed, Alexander. It can wait till morning."

"But Daniel's not breathing."

Tony vaulted out of bed. He jerked the door open, nearly crashing into Alexander in his haste. And then he was off running down the hallway.

"Jesus," Bucky said.

Alexander remained standing in the doorway, clutching his Captain America teddy bear tightly. "Is Daniel going to be okay?" he asked in a small voice.

"Of course he is." Bucky patted the spot beside him on the bed. "Tony's going to look after him."

Alexander crawled into bed and rested his head against Steve's shoulder. He was shaking a little and Steve rubbed his back encouragingly. Both Daniel and Alexander were so smart, it was hard sometimes to remember that they were both so young.

When the door reopened, everyone looked up.

Tony trudged into the room and flopped back down across the bed. "Asthma attack."

"Is he okay?"

Tony shut his eyes. "Yeah. Jarvis talked him through the worst of it."

Steve nudged Alexander. "Go look after your brother. Let us know if anything else happens."

Alexander nodded tightly and hurried back down the hall.

Tony let out a gusty sigh. "Well, I think that's quite enough excitement for one night."

Steve rubbed Tony's shoulder. "I'm sorry," he said. "I should have realized all my old health problems-"

"Hey, no," Tony said. "Not your fault. I had childhood asthma, too."

"Guhh," Bucky said. "How can you two just ignore the fact that he's in goddamn heat?"

Steve grinned. Bucky had always been pretty susceptible to heat-scent. Back in his day, he had been told that only alphas and betas were effected and it was natural for omegas to seek them out to get them through their heats. But Steve had been too frail and sickly to take even a beta and Bucky had always helped him through his heat as best he could. After a while, he and Bucky had started being able to sense each other's heats. Probably not as well as an alpha could, but he had never felt deprived when Bucky begged to suck him off.

"Oh, yeah," Tony said with a lazy smile. "Weren't you saying something about keeping my mouth busy? Don't want the kids getting traumatized. And you know how loud I get when Steve fucks me."

Bucky's eyes darkened and he dragged Tony back down into another smoldering make-out session while he helped strip him out of his clothes.

Steve groaned at the sight. This was his family. Beautiful, sexy, perfect.