What is "flip-flap"

Flip-flap \Flip"-flap`\, n. [See Flip, and Flap.] The repeated stroke of something long and loose.
--Johnson.

Flip-flap \Flip"-flap`\, adv. With repeated strokes and noise, as of something long and loose.
--Ash.

n. The repeated stroke of something long and loose. vb. To flop or flap about.

adv. with repeated strokes and noise; "something going flip-flap in the night"