A big part of being able to dominate the block on offense comes down to having great post position. If the offensive player is able to catch the ball closer to the basket their scoring percentage goes way up. So the defensive player is going to do their best to drive the offensive player out or take away passing angles for the post entry pass. This is where being able to not only get great position, but also seal off the defender comes into play.
Once an offensive post player gets position, they need to be able to seal the defender off and create a passing angle for the player entering the ball. This post drill will highlight some great teaching points for this action and then also allow for a lot of repetitions at the move itself.