fast:
This version is good for speed, and speeding.
FAST: quick, immediate.
(Stick your thumbs a little-bit between your index finger and middle
fingers. The index fingers are wrapped a bit around the outside edge of
the thumbs. When I do it, I'm resting the pad of my thumbprint on the side of
my middle finger, the nail of my thumb is digging slightly into the inner
crook of my index finger. Then I snap the thumbs up.
