Green’s Dictionary of Slang

flip-flop n.2

(US) a trick, a gimmick.

[US]Ade ‘The New Fable of the Marathon in the Mud’ in Ade’s Fables 294: The more Irons in the Fire, the more flip-flops he turned.
[US]S. Lewis Babbitt (1974) 70: I wouldn’t require [...] any of these doodads and flipflops!