The White House rolled out an official hashtag — #WHsurprise — for the event, and live-streamed President Obama, Michelle ObamaMichelle LeVaughn Robinson ObamaObama on social media: You’ve got to ‘think before you tweet’ MSNBC trolls Trump with video montage of Obama saying ‘Merry Christmas’ Overnight Regulation: USDA delays healthy school lunch requirements | Senate panel advances controversial environmental pick | Drone industry pushes to ease rules | Dem commish joins energy regulator MORE and dog Bo greeting a long line of visitors in real time.

As the first couple greeted their guests, at least some of whom appeared to be former campaign volunteers that Obama thanked for their "hard work," the president demonstrated Bo on his best behavior. The Obamas' dog, whom Michelle Obama has called her "son," repeatedly obeyed the commander in chief's order to "sit."