Literally means, typical cracker behavior.
Invented by an unknown afro-american in the early stages of the Revolutionary War. By this time, the African population in the thirteen colonies began to swell and the Africans began to learn English. So this word came into being when the word "cracker" was being used as a racial slur for the common white man. And so, much like a code, if a white man were to do something predominantly found only in white cultures, such as drinking eggnog, the black people around him/her would say TCB, almost like a code. The term has survived to this very day to still be a low-blow comment towards a white man. Most of the time, an afro-american might say it to express their sense of dumbfoundness in the stupidity of a certain action of a white man. It is most commonly used today to "diss" someone who has been "****-ing up," usually a white man a.k.a a "cracker" or a "honky."
Afro-American Man 1: What's happenin' up the hood, jeezy?"
Afro-American Man 2 (Jeezy): Nothin much, my (expletive used for an Afro-American) You hear bout this jive-turkey at that sandwich-place yesterday?
Afro-American Man 1: Naw, dawg, what was poppin' down there?
Afro-American Man 2: Well, this white boy ordered a sandwich from my friend , Stephon, and said nothing but the meat and cheese. Then, the white boy comes back five minutes later and says You forgot my mayonaise, and asks for a refund.
Afro-American Man 1: Man, damn white boys and their mayonaise. Always picky about that type of crap. Haha, makes sense, dawg, white man always gotta have his mayonaise.
Afro-American MAn 2: Mmm-hmm, that's some TCB.