This drill simulates defensive emergency situations.

Have 5 offensive and 5 defensive players line up as one guard (O1) two wings (O2 & O3) and two post players ( O4 & O5). Have one extra offensive player in each corner(O6 & O7).
As the ball gets passed to the corner(O6) the extra defender has to drive baseline. Defenders rotate over to stop the penetration. If O6 passes the ball away, after being stoped, he returnes to the corner.

Start with offensive players stationary.
If this works allow the offensive players to move.
As a third stage allow every player to dribble, drive and shot the ball.
Finish with live play.

This is a excellent drill to work on defensive vision and rotation.