To masturbate in class, often causing you to breathe heavily and make your desk quickly move up and down. Derived from the infamous Van Fap Floppy Cow, the king of in-school fap.
Person: Van Fap, what the hell are you doing?
Van Fap Floppy Cow: I'm Flapping the Floppy Cow, why would I be doing anything else?
Van Fap Floppy Cow: I'm Flapping the Floppy Cow, why would I be doing anything else?
by Bracelets January 08, 2010