The retired MMA fighter joined the TMZ Sports TV show (airs nightly on FS1) this week where he revealed his insane training regimen ... as he preps for the UFC honcho's 5-year-old beast, which he'll attempt to ride at an upcoming show.

"Next Monday, I'm getting on eight bulls," the 40-year-old said. "We're just gonna go, go, go, go."

"It's gonna be wild and crazy!"

Of course, Dana and Donald recently made a bet ... with a total of $100k on the line, if Cerrone can stay right side up on Twisted Steel for 8 seconds.

Sounds easy? Not so fast ... just three riders have managed the feat in a total of 34 runs -- and those guys were pros.

Here's hoping Cerrone is the fourth 'cause the money will go to charity.

"All the money donations will go straight to kid's camp," Cerrone said. "We're riding for a cause, if you will."