The Rebbe’s custom was to tap his foot at all times that Haman’s name is mentioned and when Haman’s name is mentioned with a title the Rebbe would tap harder.

The custom is to shake the Megillah while saying, towards the end of the Megillah, “this is the letter.”

The Lubavitcher Rebbe, of righteous memory listens to the reading of the Megillah in Lubavitch World Headquarters - 770