As used in the Hawaiian Islands, "Hang Loose or "Shocka" is used as a non verbal expression; or greeting. To tell the receipiant, that every thing will be OK, Relax, Stop looking at me w/ that stern look on your face.
( Mostly Visual) With the three mid figures folded down.
Extend the Thumb & Pinky finger out, and shake vigourously, about the radial axis of the wrist.
"Check Ya' Later Dudes,or shocka"
Driving your vehicle and you stop to let someone make a turn you stop and give him the shocka hand sign
Driving your car someone let you in a spot or make a turn you give him the shocka hand sign, as a way of saying hang loose or thank you, mahalo.