Please follow Tom Steyer’s arms during this performance of “Back That Azz Up†at a campaign rally in South Carolina last night. He waves them in the air like he just doesn’t care. Gestures to the audience to do … something. Wildly fist pumps in all directions with little regard for personal space. Raises the roof with Juvenile. Aborts an air-keyboard attempt when he realizes that, in fact, “Back That Azz Up†doesn’t have any keyboard sounds. We have a feeling Steyer’s poll numbers will jump from 2 to 69 percent after this video goes viral, even though, yes, he’s still wearing those weird ties.