With a repeated flapping movement.

(rare, chiefly in the plural, vulgar, slang) A woman's labium.

Alternative form of piss flap

(aviation) A small door on the bottom of an aircraft's cowling, used to direct additional airflow over the engine in order to improve cooling.

A hinge in the rotor assembly of a helicopter that allows each blade to have some vertical movement

An outfall fitted with a metal flap so that floodwater will not back up

plural of flap copy

The brief summary that often appears on the inside of a hardcover book's dust jacket.

(film) A failure in audio-video synchronization, so that an actor's lips move but no sound is heard.

(automotive) A small butterfly valve fitted to the intake manifold just before the cylinder head intake ports of many modern automotive diesel engines, and around which air can pass even when it is closed.