John takes Bucky's hand and gives it a firm shake.

"Don't be a stranger."

Followed by a crooked grin, because yeah, it's a little absurd to act like buddies after hanging out for approximately half an hour, but that's how John rolls. When he likes people, he likes them. It's an all or nothing deal. And Bucky looks like he could use a friend, regardless of where or how that friendship came about.

Men like them have to live life in the moment. You never know what tomorrow's going to bring. John never really counts on being alive past his next mission.