to "edge" the board (move it perpendicular to the line of movement) and brake.
or to make sharp turns while edging.
to cause the boarder to push off from a still position; it can be used the start of a race or after falling.
: Tuck the boarder to make them more aerodynamic; thus acceleration and top speed increase while the boarder's turning ability is minimized. If falling, press just before landing to absorb the shock.