You may not leave your feet to block. Each team shall designate a field captain who speaks to the refs. Charging is when an offensive player runs through a defensive player who has established position. Clipping is contact to the back of an opponent who is not the runner. Blocking from rear above the waste is permitted in the Free Blocking Zone provided the blocker was in that area at the snap.
Fumbles are dead at spot.
Muffed punts are dead at spot. Diving to pull flag is legal. Diving to advance ball is illegal. Diving to block is illegal. Any player going from ineligible position to eligible position, must report to referee.