flopping
Webster's Dictionary (GCIDE)
Flop \Flop\ (fl[o^]p), v. t. [imp. & p. p. Flopped (fl[o^]pt); p. pr. & vb. n. Flopping.] [A variant of flap.]
1.To clap or strike, as a bird its wings, a fish its tail, etc.; to flap. [1913 Webster]
2.To turn suddenly, as something broad and flat. [Colloq.] --Fielding. [1913 Webster]