Catcher gets in blocking/throwing stance. Standing 30 feet away, the coach throws a mixture of strikes and balls in the dirt to be received.
Also, mix in pump fake throws to make sure that the catcher's balance is good.
An advanced variation is to include random verbals simulating a stealing baserunner.
Yell the phrase "runner!" and instruct the catcher to execute proper footwork for throws down to second or third base.
For more information, check out my book Coaching the Beginning Pitcher.