A/N: And another Stuckony mpreg prompt. Everyone seems to want these so, here's another one XD

Disclaimer: Again, this was a prompt given to me, asking for omega verse mpreg. I'm just filling in between the lines.

Ordinarily, when they had returned from a week-long mission, Bucky and Steve would have immediately pulled Tony into a hug and several kisses. Steve would babble a lot of sentimental shit about how much they had missed him and how they were never going to leave him again. Bucky was far too practical for that and usually spent post-mission reunions trying to keep Steve kissing Tony so he'd stop talking and the kisses would turn into something more heated and then they'd all end up tangled up in bed together. Because if it weren't for him sometimes, nobody would be getting laid.

But the mission had been long and tedious and far more exhausting than a stakeout without any goddamn action had a right to be. So when they arrived home at 3 a.m. and found Tony fast asleep after a long inventing binge, neither had the heart to wake him. They just curled around him in bed and took comfort in the fact that they were home again.

When Bucky woke up four hours later, Steve was out for his morning run and Tony was still asleep. So he went down to the kitchen to make himself a cup of coffee and some maple bacon because that stuff was the shit, no matter what Tony said.

He had just polished off the plate when Tony strolled in, dressed in a nice suit.

"Meeting today," Tony explained as he stole a sip of Bucky's coffee. "Pepper didn't care that it was the day you two came back from Montana and I'd rather be fucking." He stuck out his tongue. "Oh well. You two will have to make it up to me tonight."

"That we will," Bucky said. He gave Tony's suit an appraising once-over. Something about seeing his mate all dressed up made him just want to strip him down and muss up those neatly ironed clothes. Which he was definitely going to do as soon as Tony came home from his meeting.

Tony leaned in for a kiss and then started towards the coffee machine.

"Wait a minute," Bucky said. He pulled Tony back into his arms and took a deep inhale. "Your scent's changed."

"It's a new cologne," Tony said. "Didn't realize it was that strong."

Bucky shook his head. "That's not it. It's you. You smell different."

Everyone had their own natural scent, but some events could slightly alter a person's body chemistry. And Tony had gone through more of these events than most. As an omega, Tony's scent always got strong and musky when he was in heat. And when he was in distress, which happened far too often for Bucky's liking, it was a sharper, almost sour smell. Bucky was pretty sure the arc reactor had also added a subtle metallic undercurrent to Tony's scent but because he hadn't met him pre-reactor, he couldn't be sure. But Tony's scent had definitely changed after he and Steve had mated with him. A mated omega was marked with his alpha's scent and normally, Bucky should have been bothered by another alpha's scent on his mate, but Steve was his best friend and sharing Tony with him felt so right.

Now that he thought about it, this new layer to Tony's scent was almost like his mark on him. But he didn't feel any of the instinctive anger he would feel at someone else trying to claim his mate. The scent was familiar, nonthreatening. But it was also strange and foreign.

Steve wandered into the kitchen, gulping down the last of his water bottle. His focused look faded into something fond as it landed on Tony. "Hey, babe. We missed you."

Bucky steered Tony in Steve's direction. "Something's happened to our mate's scent," he said.

Steve obligingly leaned in, pressing his face to Tony's neck where his scent would be the strongest.

Tony's mouth twisted in amusement. "Oh, come on. You two have only been gone for a week. You shouldn't be forgetting how I smell already."

Steve's brow furrowed. "No, Bucky's right. You smell…" Steve's eyes went wide. "You smell pregnant."

"That's it," Bucky said. He was smelling the way pregnancy had changed Tony's body chemistry. And the scent of their unborn child. Or children. Bucky had always loved the idea of a houseful of noisy children.

Tony snorted as he reached for a cup of coffee. "Can't be. I'm too way old to get pregnant." He hesitated. "Forty-three is too old, right?"

Steve shrugged. "You're still having heats."

"Oh god," Tony said, backing away from the coffee maker like it was a hostile robot. "I didn't think about this. I mean, I don't think about a lot of things. But this. Never in a million years would I have thought I'd ever end up pregnant. I mean, do we even want children?"

"Yes," Bucky and Steve said at the same time. They grinned at each other.

"Do I want children?" Tony mused. "I don't even know if I'll be a good mother."

"You will," Steve assured him. "I can feel it."

"I can't," Tony said. He rubbed a hand over his stomach. "This doesn't even feel real yet. How the hell can you two tell I'm pregnant before I can?"

Bucky rolled his eyes. "Face it, babe. You're not exactly in tune with your body most days. You know how often Stevie and I have to drag you out of the lab because you don't know your own limits?"

"And you have no idea you're going into heat until you're on the floor whining for us to fill you up because you feel so empty."

"That was a rhetorical question," Tony said. "But thanks for emphasizing what a bad mother I'll be. I can't even take care of myself. How will I take care of a baby?"

"Instinct," Steve said with a shrug.

"Working out great so far, Cap." Tony again reached for Bucky's coffee cup and then seemed to think better of it. "Fuck. How am I going to survive nine whole months without coffee?"

"It'll be worth it." Bucky pulled Tony into his lap and nuzzled against his neck. "Just think of six or seven little Starks running around."

Tony jumped up like he had been burned. "Whoa, whoa, whoa. Let's just start with one baby and see how it goes."

Steve wrapped his arms around Tony's waist, sliding one hand to rest over his stomach. "Don't think you have a choice in the matter."

Tony grumbled, but the slow circular pattern Steve was rubbing over his stomach seemed to soothe him. "So, baby," he said cautiously. "Or babies."

Bucky nodded. "You're going to be a great mother, Tony."

"Well," Tony said thoughtfully. "If I've survived explosions, near-drowning, falling off rooftops, electrocution, stabbings, poisonings, and mind control, I can survive without coffee for almost a year." He smiled shakily. "Right, guys?"

"Right," Bucky said. He stood up to envelope Tony in a hug. He had faith in their omega, but he knew Tony didn't. So he would really need their help to get through this pregnancy.