The act of raising your hand in a high five fashion to a stupid person but accompanied by the phrase: Gimme 6!" instead of : "Gimme 5!"
A 'Gimme 6' is a subtle and clever way of insinuating that someone you dislike is an inbred, without actually saying: "You're an inbred!"
If the inbred becomes suspicious, you can easily feign innonence and worm your way out of it by counting: "one, two, three, four, five." fingers one hand, then: "ten, nine, eight, seven, SIX!" on the other, then saying: "See? SIX!" Because they are an inbred they will buy it.
This works on their hand as well as yours.