the rule whereby if a college student is present in his dormitory and takes more than fifteen seconds to answer after a knock, one can assume that he is masturbating.
Bill: Matt, are you there? (knocking)

Matt: Yep, hold on.

(waiting)

(waiting)

(waiting)

Bill: Fifteen second rule, you're officially masturbating. (turns around)
Hey everyone! Matt's masturbating!
by The Iron Fist January 6, 2009
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