Somewhere along the way, between the party and the car, Steve felt like he'd missed a step. He'd been distracted by his nose, trying to staunch the blood so that it didn't get everywhere, and he hadn't quite realized how badly upset Bucky was - not until that dull thump properly registered as Bucky hitting his head against the headrest. Steve jerked a little, as if about to say something, but Natasha beat him to it, talking Bucky down in a low, husky voice. It sounded like she'd done this before, like she knew what Bucky needed to hear, and Steve felt suddenly wrong-footed. It was like the emotional equivalent of feeling too big and too clumsy, not used to the extra inches and the muscles he was carrying around now. It felt wrong that someone else would know better what to do for Bucky than he did, but Steve knew he'd say the wrong thing if he opened up his mouth, and so he simply watched, his brow furrowed with concern, as Natasha murmured and Bucky replied - confessed, really, like it cost him something to admit this.
Me too, Steve wanted to say, but didn't get the chance, because Natasha already had this covered, apparently. If that desire to hurt someone was what was upsetting Bucky so badly, well, Steve had been right there with him. The guy had deserved it, no question, and Bucky shouldn't feel... however he was feeling because of that.
Natasha's sudden request that Bucky touch her neck caught Steve off guard, and it took him a moment to puzzle together why she wanted that. From the gossip at the party, it sounded like people thought Bucky had given Natasha those horrible bruises Steve had seen a few days ago, but that wasn't - that couldn't be the case. Bucky had said Natasha picked him, and Natasha had said he'd done it to help her - but what was "it"? Had she asked him to hurt her? As a favor? But why? And even then, Steve still couldn't make himself believe it. Bucky wouldn't have agreed to it.
Still, this was clearly meant as an invitation for Bucky to prove - to himself, far more than either of them - that he wasn't a danger, wasn't violent or frightening or a threat to be held at arm's length.
Steve checked his nose, which seemed to have finally stopped bleeding, then roughly wiped the, unfortunately, rather bloody napkins across the lower half of his face. It just... didn't seem like a good idea to face Bucky right now with a face covered in blood. Once he was relatively certain he was presentable, Steve wiped off his hands, shoved the napkins into a pocket, and turned toward Bucky, who was angled away from him. He was trembling, the unsteadiest Steve had ever seen him, and it was miserable to behold.
"Hey, pal," Steve said softly - not wanting to detract from Natasha's words, but... wanting to let Bucky know he was here, too. "Hey, Buck. S'okay if - I'm gonna touch you, all right?" Because Bucky had welcomed it before, had obviously drawn comfort from the hugs Steve had given him, and that seemed like an okay risk for Steve to take. So he waited a beat, for Bucky to voice a protest if needed, then oh-so gently settled his palm against the center of Bucky's back, smoothed it slowly up to his neck, where his thumb stroked over the warm skin he found there.