The SIMP plays an American Scramble format.
It is a scramble format meaning each player will hit a shot, and the team can decide to play their next shot from whichever is the better ball.
However, there is a twist. It is an "American" scramble and thus each team of two will start from the white tees at the 1st. After the 1st hole the score you make on the hole will determine which set of tees you play from next.
If you hit a ball out of bounds, lose a ball in the woods or the water, simply add +1 stroke to your score and play the ball from in play where it went in. We like to keep things moving.
You may take a club length "preferred lie" so long as it is no closer to the hole and you may not improve your lie surface (meaning, you cant go from rough to fairway or bunker to rough etc.)