Red Ball Express.

Mickey Squires (billed at the time as "Colt Superstar") plays a delivery guy, bringing moonshine to various places, while Jayson MacBride gives him delivery instructions. An "on the road" device, where Squires keeps going to places where sex is happening, or about to happen, but he's never involved until MacBride instructs him to come back to the dispatch station, and the standard, but oh-so-hot orgy ensues.