A phrase used when you have absolutely no idea how to answer a question, or piss someone off. Highly recommended phrase to be used during business meetings.
Important Guy: "Mr. Smith, how long do you think the proposal will take?"
"Timmy, what is the world's largest continent?"
"Your mom."
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"Hey, what are you doing this weekend?"
"Your mom."
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"Hey, who do you plan on making pseudo-sexual comments about?"
"Your mom."