Upon the act of coitus of the "doggy" variety, the male partner (cowboy) grabs the hair (mane) of the female partner. In this instance the female partner will be referred to as a Bronco. At this point, the cowboy, whilst maintaining a firm grasp of said mane, yells (in a western drawl): "I have AIDS, syphilis, fleas... ect." Soon thereafter, the Bronco, in a futile attempt to escape the "8 second ride", will start the buckin' process. This is known as the "Buckin' Bronco"!
In a feeble attempt to dislodge my tube-steak from her gully-hole, she flailed and kicked like a buckin' Bronco. Yeehaw!!!