To predict, criticize often after results are know. This normally occurs from a person who you are having a conversion with and is trying to demerit someone else or you.
From Showtime series Weeds Season 3 Episode 7-He Taught Me How to Drive By Marvin: Are you second guessing me bitch?!
Utterly pointless use of the word "second" to convey no additional meaning but with the intention of appearing more intelligent than in fact. Much beloved of political reporters. See also Anytime soon.