Falling without hope of surviving, arms and legs flailing about.

Dark hair flying, legs flailing, she hit the water with a splash.

His arms and legs flailed wildly, then, suddenly, fell completely still.

The head remained nearly still while the arms and legs flailed furiously.

His arms and legs flailed like those of a cat flung from a high window.

The legs and arms flailed for a few seconds.

His legs flailed wildly for a moment, then he slipped over the side and into the canal.

Ghost was twisting and snapping, legs flailing in the air, but he could not break free.

Arms and legs flailed wildly, fell still for a moment, then began twitching again.

Arms and legs flailing, he snatched frantically for something, anything solid.