The initial idioms of the letter B

beat off	beat on
beat one’s brains out	beat one’s brains out to do something
beat one’s gums	beat one’s meat
beat one's brains out	beat one's head against the wall
beat oneself up	beat out
beat someone/something out	beat someone’s brains out
beat someone at his or her own game	beat down
beat something out	beat swords into ploughshares
beat the	beat the air
to beat the band	beat the bishop
beat the bushes (for someone or something)	beat the bushes for
beat the bushes	beat the clock
beat the daylights out of	beat the drum
beat the drum for someone/something	beat the dummy
beat the Dutch	beat the gun