MARINE CORPS BASE CAMP PENDLETON, Calif. -- Half an hour before show time, Cpl. Greg Simpson starts to get ready."I'm going to go change my britches," he said, tossing a pair of jeans over his shoulder.When he returns, Simpson changes into red cowboy boots, which he straps on with a piece of rawhide - a precautionary measure to keep his spurs on his boots and his boots on his feet.Finally, he prays.All this and more for a job that lasts no longer than eight seconds.When Simpson rode his first bull at age 15 in his hometown of Wildwood, Mo., he fell in love with the sport. It only seemed fitting, though, since his father and grandfather were pro saddle bronc riders. Simpson earned a bull riding scholarship to Missouri Southern College in Joplin, Mo., but spent so much time riding that he lost it by the second semester.His father told him he needed something besides bull riding, so Simpson joined the Corps."The Marine Corps just comes naturally to me," he said. "It's the second most natural thing after rodeo."Despite any natural talent or bull riding genes, Simpson practices at least two hours each night riding a 55-gallon drum, ingraining reactions to his muscle memory depending on how a bull bucks, spins or twists. Good bull riders react to the bull subconsciously as the result of training, he said."My best rides, I don't even remember," Simpson said.Today, Simpson is a professionally ranked bull rider who hopes to ride in as many as 120 shows this year, some as far away as Florida. Marines rated in professional sports can be allowed time off work to participate.Last year, Simpson won the Camp Pendleton Rodeo and the Armed Forces Rodeo Association finals at Twentynine Palms, Calif. In his last three pro rodeos, he's placed at least third.