bucking bronco

noun4

1. •
   A wild or untamed horse, characteristically difficult to ride.
2. •
   A mechanical bull in the form of a horse.
3. •
   A spirited or uncontrollable person.
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.