The "TMZ After Dark" tour is one of the wildest parties in all Hollywood ... and, Jerry O'Connell busted out some crazy dance ...

Chanel West Coast brought the cowgirl spirit to the "TMZ After Dark" tour ... singing a couple of country tracks for riders and jumping on a mechanical bull!

Alright, partners, you better saddle up, because we've got plenty of celebs trying their hand at riding mechanical bulls!