Did... Did Tom just poke fun at Steve? Did he just pull Steve's leg? O_o who is he and what has he done with the Tom we know?

And a SMILE?? I think the world just fainted.

To be fair here, Tom and Steve share a very comfortable relationship. That might seem strange because by this point there's only been perhaps 3 years since their reunion. (After a six year stint of thinking each other dead). It isn't the easiest relationship, because their interactions tend to be tainted by what they remember of each other from before - which as you can guess causes friction.