I believe that this one is pulled totally from my own fat old lady brain.
At some point in my misspent youth, I started saying:
“And my ass chews crackers too.”
The general meaning of this is akin to “Pull the other one, it’s got bells on it.” Or simply, “Yeah. Right.”
I said this once to a legal secretary and she said, “WHAT?”
I repeated the phrase to her slower and she said, “Oh. That makes a lot more sense. I thought you said ‘Cracker stew’.”
Of course, I immediately fell in love with that wonderful abbreviation.
I seldom use the abbreviated version though because my experience is that most people immediately understand “And my ass chews crackers too” but are baffled by “Cracker stew” – even with an explanation. So take your choice. They are both satisfying and useful phrases.