Okay, so in a way this is kinda going to be set like the werewolves in Twilight. Basically Bucky and Steve are humans yet they can form into wolves. There is mpreg involved.

Stucky

Bucky and Steve were raised by wolves, well humans that can turn into wolves. Sadly, these types are people are banished to a place where they can live with others who have the same thing. It is mainly just a forest filled with mountains and caves, this is where majority of the wolves live as they're no houses and they like it that way.

However, they say it is best place they can be as there are no normal people out to hunt them or test on them. The wolves just live their lives, they act a whole lot more like wolves than humans as it's just in there nature.

Wolves are wolves.

"Hey Baby. How're you and the pups." Bucky smiles at his tired Omega, boyfriend,
"I'm good, just tired." Steve sits wrapped around his litter as they sleep up close to their male mother,
Bucky gentle pads over and curls up next to Steve, he changes into his human form as they are alone. He strokes Steve's silky, brown fur "Anything you need? Want to get some rest and I'll watch them."
"That'd be great, thank you Buck." He changes into his human form too and grabs Bucky's hand lacing there fingers together "Give me a kiss, Jerk." He laughs lightly,
"You little punk." Bucky grins leaning over and places his lips to Steve's, as they kiss one of the pups let's out a whine. They pull away and Steve goes to comfort them but Bucky stops him "Sleep. I've got them."
Steve smiles fondly and snuggles up to Bucky closing his eyes and falling asleep almost instantly.

Bucky gently takes the four pups into his arms, two girls and two boys. They hadn't really decided names yet as they wanted them to grow a little more, they were only just over a week old.

A few hours later and Bucky's ear perk up at a sound, he nudges Steve "Baby, Steve wake up please."
Steve's eyes open "What, what's up?!"
"Shh, I think someone's coming. Take the pups."
Steve nods quickly and takes his children and goes further into the cave, where it's darker and he can't been seen as much.

Bucky changes into a wolf and stalks out the cave, teeth shown and making low growls. He pokes his head out and sees two their alphas, one slightly bigger than the other, coming up. "Fuck sake, why can't we just be left alone." Bucky barks,
"Please be careful Bucky! I love you."
"I love you too Babydoll, everything's going to be fine."

Bucky goes out and stops the two wolves in their tracks "Why are you here?"
One just smirks "Barnes, nice to see you too."
"We just came to check up on you and see how your omegas getting on, with his new litter and that." The other laughs lowly,
"Leave now, you're going now where near him!" He snaps,
"Oh really! Well I'll take that as a challenge."
Bucky rolls his eyes "You know I'll just knock you off the the side of the mountain it's really not hard." He flashes his metal arm in the sun. The shorter of the two backs away a little, yet the bigger moves forward "Let's go Barnes."

He launches at Bucky and he's quick to stop the other alpha smacking him straight in the face with his metal arm. He flies backwards but stands back up and manages to scratch Bucky on the face, he returns it and head-buts the smaller. They both jump at Bucky and Bucky ends up on his back yet he's a strong fighter, he bites the large on the leg and he howls in pain as he moves away from Bucky.

Bucky shoots up onto his hind legs and grabs the shorter, hitting him multiple times until he's bleeding quite a lot. He lets go of Bucky with a whimper and runs off limping. The bigger is still putting up a fight "Coward." He mumbles "Well, well, well, now it's just us."
Bucky hums and runs forward catching him off guard, he slashes his face again and punches him in the nose. He jumps and kicks his legs knocking him to the floor, this time he doesn't get up. Bucky continues to kick him until he's begging "Please, I'm sorry." He coughs out blood,
"Don't ever come back here again you hear me!" Bucky roars,
The wolf nods and scurries away.

Bucky carefully wanders back into the cave, his face and side hurting. "They're gone Stevie." He says as he falls on to the wall, slouching down,
Steve gently puts down the pups and runs over to his lover "Bucky! Oh my god your face!" Steve puts his hand over his mouth.
"Don't worry about me. Look after the babies!"
"They're fine Buck, they're safe and sound now you saved us."
Bucky's eyes softened, he pulled Steve into his arms.

Steve let out a small sob, which then lead Bucky to release his tears. He didn't realise how much he had built up. "What are our lives Stevie?"
"A bit of a mess Buck, but we manage."
"We do." Bucky repeated a few times before standing up with Steve, they walked over to there pups and Steve changed into his wolf form so he could feed them. Bucky smiles at his family, he loved them with all his heart.

Steve turned his head to look at Bucky "We'll be alright."
"We have each other." Bucky joined Steve in his wolf form, as his lover wriggled into Bucky's embrace. "I love you all."
"We love you too. You're the best dad and the best boyfriend anyone could ever ask for."
Bucky was sure his heart melted a little at that "You too baby, you too." He whispered softly into Steve's ear.