Bucky knew Clint had figured some of it out, since he'd known Bucky and Natasha sleeping together and Natasha ending up battered afterward hadn't been real. And from there, he'd know that leaving the party together probably wasn't either. Plus Barton was closer to Natasha than Bucky had been, so he'd probably know her play. Telling him wasn't much of a risk, and he'd acted like he'd wanted to know - like he'd feel better hearing the no-bullshit version, maybe? So Bucky could do that for him. He hadn't done much else for the guy lately.
Plus, it was just easier not to have to lie one more time to one more person. He understood that living a lie was how you survived most of the time, and Bucky tried to do it. But it didn't mean he liked it. Honesty with people who understood always felt like a relief. Bucky laughed, taking a bigger sip of the tea - he should have put it in something easier to tip back - and shaking his head. "I've got a chocolate bar and some croissants. I can see what I can do, but it's not gonna have much dignity when it melts on your head," Bucky told him, smirking. He made a face. The thought of the Quarter Quell and what might come with it usually was enough to pull Bucky into a black hole of worried thoughts about it. But he just circled around the edges of the vortex and kept clear with a little grimace. "Think they won't try again for a while anyway - be too much the same thing, probably. They like to keep it fresh," Bucky made a mocking sort of hand gesture that made no sense, and Moo just tried to swat at his hand, making him laugh again.
"You like Clint? Or Barton? Or ... Clinton?" Bucky asked, smirking a little. "Mr. Barton?" he teased. He groaned and then picked the kitten up in his right hand, holding her up to his face. "Moooo," he said, making the noise and then snickering when she just put a paw on his mouth, as if to shut him up. "Do I need a saddle? You ride cows, right?"