Red Ball Express (1981)

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