Get the bit between (one's) teeth Verb + object/complement
"Get" can be replaced by "take".
To start doing something decisively and energetically
Once he loves it, he gets/takes the bit between his teeth and there's no stopping him.
By getting the bit between his teeth, he worked his way to the top.
As long as she gets the bit between her teeth, I believe that she will become unrivaled in her class.
Can't wait to do something
Ecstatic and mentally ready (for something).
Someone who is very determined to do something or achieve what they want
The verb " get" must be conjugated according to its tense.
A bit is a mouthpiece used to control the motions of a horse. It's usually set up so that pulling on the reins causes the bit to rub into the horse's soft parts of the muzzle, forcing it to turn its head. This term refers to a horse chewing on the bit and wresting authority from the rider. The expression first appears in John Dryden's satirical poem The Medal, published in 1682