bucking bronco

1. A wild or untamed horse, characteristically difficult to ride.

   a wild horse that is vicious and difficult or impossible to break in

2. (broadly)A spirited or uncontrollable person.

3. A mechanical bull in the form of a horse.

4. (humorous)A supposed sexual position that involves the man telling the woman something disagreeable during sex (e.g. that he has a sexually transmitted disease, or prefers another woman), causing her to struggle or lash out.

regular