"Right, because you're the expert on fireworks" Dean's tone is still teasing, and mostly good-natured teasing at that, though it would be a lie to say there isn't a little bit that's still raw from the Worst/Best Christmas Ever and wishes Sam wouldn't question things quite so often.
He grabs his gloves anyway, makes a bigger deal than necessary of waggling them at Sam to show that alright, he's taking them, so can they drop this please? before shoving both into one pocket as he gets his own jacket.