Real Dictionary

champ at the bit in British English
to be impatient to start work, a journey, etc
to betray impatience, as to begin some action
to bite upon its bit repeatedly and restlessly
to want very much to do something, but be prevented from doing it, usually by a situation that you have no control over

champ at the bit to chomp at the bit
phrase: If someone is champing at the bit or is chomping at the bit, they are very impatient to do something, but they are prevented from doing it, usually by circumstances that they have no control over.