A coach or infield leader will yell double cut.  Double cuts are needed when a ball is hit to the fence and there is gonna be a long throw to a base.  On a ball hit to the left field gap and the play to be expected at home, the SS will be the lead relay guy and the 2B will be the trail man incase the ball travels over the SS.  The 1B will be around the pitchers mound as a cut-off in direct line with the relay guys and home plate.  The pitcher will be backing up the catcher.