Bucky knows what Steve wants because he wants it too.
He can't. Not until he's had some time to figure out who Bucky Barnes is now that he's free from HYDRA. The programming is cleared out of his head but he's got lifetimes of scars to work through before he can give Steve what he deserves in a partner.

He smiles fondly, giving him a chuck on the shoulder. "Pretty sure that's not what they do out here, punk. But I'll remember."

"I'll check in when I can. At least once a week."