The lapel grab is a common attack in which the enemy tries to control your body and position so as to strike you more easily and accurately. Ideally, you want to keep the enemy from grabbing your lapel and striking your head/face; however, sometimes you will be grabbed. This bunkai drill from Pinan Nidan/Heian Shodan provides one way to deal with a lapel grab attack. The video also demonstrates a throw, based upon the pivot into low block that comes at the end of the high-block sequence.

Best,

David