MST3K episode, hard to find with these two memories.

It was a Joel episode, the first Joel one I ever saw... and I don't remember which one it was. I remember two Joel quotes: "Crap-a-mundo" and an air hump. Literally it. It's been bugging me for a while.

This is a tough one. Night Train to Mundo Fine (a.k.a. Red Zone Cuba), maybe?

As far as the air humping goes, I asked someone on the MST3K Reddit and got this answer: "The closest Joel ever came to "doing an air hump" is the final segment of 404-Teenagers From Outer Space. And its a still-image of Joel in a duct tape sailor suit on top of the SOL desk. But even that's a reach."

Hope that helps.

EDIT: I've also been informed that Joel does an air humping-like dance in Time of the Apes, Gamera vs. Guiron, The Beatniks and I Accuse My Parents.

Thanks. But I guess I should've specified: both jokes take place during the film, not in a skit. Joel stood up from his seat just to do it, and I think it was in the middle of a conversation between two or more in-movie characters. I hope that helps your sources.

Oh well. Fire Maidens from Outer Space and Pod People i(it stinks!) are other suggestions someone made. Good luck!