USMA slang. Euphenism for the act of masterbation. Can also substitute pretty much any other college in place of Annapolis i.e. "Beat Air Force!" or "Beat Texas!"
P - "Beat Navy, Sir!"
F - "Don't forget to wash your hands."

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P - "Man, I barely have enough time to do homework, let alone Beat Navy every now and then."
by Mavrck August 26, 2008
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