The initial idioms of the letter B

be knee-high to a grasshopper	be knocked out cold
be laughing all the way to the bank	be laughing on the other side of face
be laughing up sleeve	be left hanging
be left holding the baby	be left holding the bag
be left to (one's) own devices	be left to (one's) own resources
be like a bear with a sore head	be like a bull in a china shop
be like a cat on a hot tin roof	be like a red rag to a bull
be like oil and water	be like rearranging the deckchairs on the Titanic
be like ships that pass in the night	be little love lost between (two people)
lock in	be long for this world
be lost in translation	be lost on
be main squeeze	measure for drapes
be meat and drink to	be meat and drink to (someone)
be miles away	be minting it
have all one's buttons	be money for jam