A double fake is a deceptive strategy that the quarterback typically uses when he pretends, or fakes, throwing the ball to one person before passing it to another player on the opposite side of the field. This maneuver is used to deceive defenders by having them lunge one way to free up the wide receiver for just a moment and create possibly create an open lane on the other side of the field. It's performed by having a player wind up to throw the ball, but then not releasing it, then turning and throwing it to an entirely different area of the field.
Quarterbacks use double fakes to try to trick defenders. It is one of many trick plays that they can use to fake out an opponent. The double fake is effective because players are always keeping their eyes on the ball. If they see a player about to throw the ball one way, they will react by lunging that way.
There are almost no risks when a quarterback performs a double fake. It is possible that if he takes too long to throw the ball, the quarterback could be sacked. But other than that, there aren't any safety precautions to consider. Although most trick plays are risky, the double fake can be performed at nearly any time during the game. It's hard for defenders to avoid the double fake when they don't know it's coming.