This play is just a wrinkle to a regular double option play. Instead of having the QB option the pitch key defender (see circled player in diagram), the B-Back will carry out the option. Upon the snap, the QB will immediately toss the ball to his B-back. The B-Back then attacks the pitch key defender (first defensive player outside the DE). Note: a stacked LB counts as a player outside the DE. Depending how the pitch key plays the B-Back, he will either take the ball up field, or pitch it to his trailing A-Back.