This is one of those high school baseball drills that make practice fun and energizing. The kids love it because there is no standing around, it's fast paced, and they get the chance to play defense, hit, and baserun. Most importantly, the players get a chance to compete and the coach gets a chance to see who can produce under stress. 

Purpose: To create live offensive pressure to execute an offensive play. To develop base running skills when the ball is hit, to develop hitting skills for a particular situation, and to develop a team defense in reaction to the hit ball. 

Procedure: Approximately a 20-35 minute live batting station with a full defense. The hitters will execute a given play and the base runners will execute as well. The defense will defend all hit balls as if in a game. 

Coaching Point: Play solid defense and offensively keep the ball in play. 

I wrote a baseball drills pdf about this part of practice.  The PDF Ebook name is 4 Man - 4 Team Practice Plan.

This is a pre-designed practice plan that will allow you to work on situational hitting, game-like defense, and game-speed baserunning.  All of this happens simultaneously in a highly structured intrasquad game. 

This practice moves along fast as there are four rotations with each rotation moving at a specific time decided by the coach. 

Excellent practice plan when you are the only coach on the field.