Man, some people need instructions on how to pick their nose.

You take your left hand of the handlebars & wave it in the air.
If you already know how to busta move, it'll look cool. If you don't, it'll look as klutzy as everything else you do.
PS If I'm coming out of a good set of twisties, I'll give opposing riders either a thumbs up, or a thumbs down, to indicate whether there's any cop action happening. & if I know that they're heading into an imminent speed trap, I'll give the time-honoured slowdown signal of repeatedly pushing down emphatically with my hand.