When someone is caught lying. How now is self explainitory. Brown Cow means that they are a liar. Works incredibly well if they are exposed for their lie.
Guy 1: Hey, I know what the capital of Illinois is. It's Chicago.
Guy 2: It's Springfield. How now brown cow?
Guy 2: It's Springfield. How now brown cow?
by gbee93 April 09, 2011
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