Have the pitcher take the proper angle to first and have the first baseman deliver the ball. Continue rotating through players. It's a good idea to run this drill with a runner starting from behind home. This will help both the pitcher and the first baseman get a feel for the speed and timing that is required. It will also reinforce the need for the pitcher to not cross the runners path.
Pitchers get to work on communication with catchers.
Have the catcher in position with the mask on facing away from you and towards the pitcher. Throw the ball up in the air and when it get's near the top the pitcher will point and give verbal directions to the location of the ball. The catcher must pick up the direction from the pitcher and then find the pop-up. The catcher should work on carrying and then tossing the mask properly. It's difficult to be able to hit the ball up the shoot for catchers to practice catching a pop-up.