Oddly hard to describe but basically the thing from the Men on Film skits on "In Living Colour". ( I am shocked I could not find a video clip to use as referance) Or just about any charachter on this page http://tvtropes.org/pmwiki/pmwiki.php/Main/SassyBlackWoman
It is all *snap* *snap* *head whip* that I have only ever see people on tv who are "sassy" do.