Rollo is telling mule-skinner jokes to Ryan, who is a mule skinner. Finally Ryan's had enough. "Listen, give me a break, tell me a joke about people other than mule skinners!"
Rollo: "Okay, who do you want in the joke, then?"
Ryan: "Oh, make it about saddle tramps. Can you do that for me?"
Rollo: "Certainly my man, okay, let's see. Got it! There's these two saddle tramps, see?"
Ryan: "Yeah?"
Rollo: "And they're skinnin' this mule, see?" . . .