If a player drives the dirt, with the ball, a hard body check is permissible, below the shoulders. If a player is receiving a pass, in the dirt, and a hard poke, stick check or firm bump will stop the play, OK. But to take two steps or more and bury him will be flagged.

Ground balls- play the ball first. Approaching a ball from opposite directions, play the ball. In a 2v1 GB, its Ok to run a player off the ball or knock him off track.

It really isn't that complicated. Play the ball first. Attack a ball carrier. Players competing for a ground ball or a pass, play the ball first then body him not bury him.

Smacking the back of your sones head and punching him in the face will both get his attention but one is highly unnecessary.