take the bit in (one's) teeth

take the bit in (one's) teeth

To do or begin doing something with decisive, independent resolve. A reference to a horse that is no longer under the rider's control because the bit (part of the apparatus used to guide it) is out of place in its mouth. You have such potential, Sophie—if you ever just took the bit in your teeth, you'd be one of the top students in this class. Rather than kowtowing to the president's public frustrations, the attorney general has taken the bit in his teeth and pressed on with the criminal investigation.
See also: bit, take, teeth
Farlex Dictionary of Idioms.

take the bit in one's teeth

 and take the bit between the teeth
to put oneself in charge; to take charge. Someone needed to direct the project, so I took the bit in my teeth. If you want to get something done, you've got to take the bit between your teeth and get to work.
See also: bit, take, teeth
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • take the bit in (one's) mouth
  • take the bit in one's mouth
  • take the bit in teeth
  • get the bit between (one's) teeth
  • get the bit between your teeth
  • get/take the bit between your teeth
  • have the bit between (one's) teeth
  • have the bit in (one's) teeth
  • take the bit between (one's) teeth
  • take the bit between the teeth, to