The episode: “Posture Pals,” a short before “The Unearthly,” ep. 320
The riff: Inserted by Joel as a teacher informs her students about the basics of proper posture. She tells them that “arms are easy at the sides, eyes straight ahead, shoulders relaxed…”, at which point Joel adds “…and you truck like the doodah man.”
The explanation: This is apparently a direct reference to the 1970 Grateful Dead song “Truckin’,” which goes “Truckin’–got my chips cashed in. Truckin’–like the doodah man.” Servo confirms the riff by muttering “Ooh…got your chips cashed in?” under his breath right after Joel delivers the line. The original lyric is apparently a reference to a group called the “Bonzo Dog Doodah Band” that the Dead were fond of.
Novelty factor: I had no idea, nor do I truly understand the riff even now. I think he’s basically trying to compare the teacher’s lesson to dance move instructions, but overall I may have to chalk this one up to Joel’s oddball sense of humor. Moreover, I think the way Tom Servo adds a little snippet of the lyrics himself shows the writers of the show almost poking a little bit of fun at the obscurity of their own reference here. They’re practically daring you to know what they’re talking about.