Table manners are so very important. And setting a good example is a must. Here we see that Verta is sternly reminding young Bobby that cavitating at the dinner table is a “No-No.” Of course Sally is about to bust out laughing because it’s always funny when your sibling is in trouble and you’re not. But Bobby has a questioned look, because he didn’t do anything….it was ol’ Dad, Vert, who committed the cavitating act, as he covers his face in embarrassment.
Explanation: A cavitation is the fancy way of saying that a joint “popped” or “cracked”. If you still don’t get it: cavitation = fart.