It was probably stupid -- Clint had plenty of stupid thoughts and ideas at any given moment -- that Bucky's use of sign language was... maybe something that pushed his like a little further over the line. He didn't know why, it just did things for him. A lot like Natasha offering to learn, if he would teach her did things for him. It was just - it felt very personal. Of course, the thought was as useless as it was stupid because there was still no acting on it. But it was something that'd be in his head for a while to come.
And of course Bucky wouldn't ever try and come between what Natasha and him had, Clint knew that, okay? He did. Because he'd tried telling Bucky he ought to have what he wanted and deserved before and all that had done was get him a very harsh scolding from the two of them. Natasha had been upset at first because she'd thought Clint had been lying to her, or that he had changed his mind about it -- a miscommunication that in retrospect, Clint could see how it might come across as such.
But Bucky? He'd been mad because he saw through Clint immediately, and wouldn't stand for a minute of him devaluing his self worth so intensely. There'd probably never be a time when Clint truly, fully believed that he was everything that Bucky and Natasha saw in him, but it had meant a lot to be reminded that he should at least try and value himself more properly.
Clint didn't want this, whatever it was, whatever he'd enjoyed the very most about hanging out with Bucky -- the ease of it, the slight flirtation even, to go weird and bad because he'd not known how to respond, or because Bucky felt awkward and unwanted. His face probably reflected that, eyebrows dipped down and mouth a crooked line of uncertainty.
But Bucky bounced things back to something more simplistic before he could figure out exactly what it was he wanted to say, and Clint couldn't help the laugh that just sort of burst out of him, surprised and delighted and somehow still a little sad. "Favorite," he signed nearly without thinking. "No one's ever gonna top your spot," he promised. "There's no centaur better of sexier, and no mervenger that even holds a candle." He paused, glancing away for a second, considering. "Hey. It's big of you. To tell me. I'm not sure I woulda had the balls."