1. A quick masturbation session, or quick sex. Or a statement that one is busy, but only for a short period of time. Can also be used to refer to a third party's where-abouts in a joking manner.
"Got caught having a quick biff this morning"

"She told me to meet her in the bathroom. A quick biff later and im back at my desk working."

"Whats up?" "Quick Biff" or "Brb, quick biff."

"Where did Ben go?" "I dunno...quick biff?" "hahaha"
by RobberCrook June 3, 2009
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