Verb
bite down (third-person singular simple present bites down, present participle biting down, simple past bit down, past participle bitten down)
To clench with one's teeth or to bite hard on something.
Why are we designed to see the world as supremely beautiful just as we're about to be snuffed? Do rabbits feel the same as the fox teeth bite down on their necks? Is it mercy? Margaret Atwood
I'm scared every time I go into the ring, but it's how you handle it. What you have to do is plant your feet, bite down on your mouthpiece and say, 'Let's go.' Mike Tyson