take the bit in one's mouth

Idioms and Phrases

Also, take the bit between one's teeth . Throw off restraints and proceed on a headlong course, take control. For example, My partner took the bit in his mouth and bid a grand slam , or Jane took the bit between her teeth and now there's no stopping her . This idiom alludes to the bit , the metal mouthpiece of a bridle whereby a rider controls a horse. [c. 1600]