The first clue Bucky had that something weird was going on was when something whimpered from the other room. Steve had never been the whimpering type--he was more the 'clench your teeth together and keep mum about it until it's over' type, which went double now that he was all big and handling Bucky with kid gloves and everything--and besides, it sounded an awful lot like a...
"When did we decide to get a dog?" Bucky asked, dumbfounded, when he looked into the living room and saw Steve with a punch of plastic bags from Petco hanging from his left hand, and some sort of wiggling mutt tucked under his right arm.
By the time he finished asking, Steve had deposited the puppy on the floor. It immediately started exploring, wiggling its entire backside as it sniffed around the room (and thought about raising its leg on the sofa, probably).
"I got him for you," Steve said. "He's about four months old, the shelter said. Happy birthday."
"What made you think I'd want a-- wait. Is it really my birthday?"
"Yep."
March 10th. Bucky was going to have to remember that. "Why'd you go and get me a puppy, Steve?"
'Without even asking me,' he might have added, but there'd have been no point. When Steve decided he wanted to do something, he was going to do it; asking other people's opinions would only slow him down.
"You need something to keep you company when I go on missions," Steve said immediately. "You still like dogs, don't you?"
Bucky could have said no. Making up some trauma about Hydra siccing mutant dogs on him was probably the only thing that could have gotten Steve to take the puppy back to the shelter. But the puppy had made its way over to him now, and was sniffing his shoes; and when he reached down to pet it, it started licking his hands--both his hands, not seeming to notice the difference between the two--and wagging its entire butt even more.
"You should have something to take care of," Steve added.
Bucky could have said something like, 'What makes you think I'd be safe around a dog, anyway?' Part of him wanted to. But that was just a reflex, from the first couple of years after, when he'd been ten times as reactive and jumpy as he was now, and hadn't dared to do much more than follow Steve around from a distance. So, instead of that, he said, "What, you don't think you need taking care of anymore?"
"Sure I do," Steve said at once. "And so does this little guy, now."
"Great. That's just great," Bucky said...but Steve was right: he really had always liked dogs. Loved them, even. He'd have had one before the war, if they could have afforded to feed a pet on top of the two of them. So he really couldn't be all that mad about it, in the end.
At least, not until the puppy whizzed on the floor and Steve said, right away, "Guess you'd better clean that up."
"What makes you think I'm going to do it?"
"Well, it's your dog, isn't it?"