The guy is veterinarian, pulling several horses in his trailer in hot weather, trying to get them home and to some water.
The girly-boys and girls are riding side by side on a country road, chuckling how they're holding up what they think is some dumb country goober.
Finally, they pull over at a store, going to get a drink or something.
The Doc pulls in behind them, walks over to one the chicks bikes, bends over the seat acting like he's big sniff, then he starts going off on a real loud rant in front everyone (paraphrase), "Woo-ee, that sure does stink! Smells just like the livestock I work on, whew-we!!..."