Lower the Boom

Etymology:

• We know that a boom is a long rod or pole that is used on ship to lift cargoes up in the air. These long arms or booms are also used in theaters backstage to move a set or scenery. Although it is hard to imagine a long boom on you as it will badly hit you or probably knock you out. So as the phrase suggest to lower boom means to beat someone or it could also be used to mean scolding someone badly.