You do dontcha ROFL... Wavin at the bushes J ???
I never really thought about it. Mine was always just lift the left hand about 3 inches and point at them casually with 2 fingers (index and the one next to it), kinda like a sideways one-two peace sign. I always did it to cops as we passed on 2 laners just to acknowledge I was aware of the road, and most flicked a wave back through the widshield. Really only a couple looked staraight at me and snubbed.