1. A polite and well meaning colloquialism used to express agreement with a cohort. (This phrase entered american vernacular when famed celebrity/artist/rapper/pornographer/movie star Snoop Dogg started using it and other words containing the suffix "izzle" or "izzy.")
2. To aquiesce to or agree with a proposition or idea offered by an affable peer.
My Boy D-Bo axed me if I was going to the game tonight... I said "Fo' Shizzle my nizzle" in the pitch of a tenor.
not necessarily in any racial context.
From a branch of urban (American) slang which adds 'izz' or varients of (ie izzle/izzo) to words to create a more rhyme like 'melody' to sentences.
kid 1: "It's late, I'm heading back to the hizzous... you stayin?"