He is the class cown kinda character obviously. Saw similar stuff in his Man U days, vids of their locker room, the one to allways goof around/prank others. Unserious character kinda character. In serious sitautions on the pitch, he is usually just normal/the calming type (unlike Valdes, wannabe Montero he is).
And lol, playing around with people you know is normal, slapping someone on the head and then pretend you didnt do it is a typical childish prank.