When Russians say that you are like a grass snake on a frying pan ("как уж на сковородке"), they often mean that you are grilled by tough incriminating questions and desperately trying to save your face by dodging questions and creating explanations on the fly. The idiom can also mean other things.
I wonder how Russians could come up with such a bizarre idiom. Did Russians use to eat grass snakes in the past? Did they fry them alive? Or is the idiom just a product of too wild imagination? Intrigued, I found quite a few Russian recipes of cooking grass snakes - e.g, this one...
I was unable to find any serious source explaining the etymology of the idiom. I only saw a folk etymology hypothesis that the idiom was born by merging two different idioms, "like a grass snake" ("как уж") and "like on a frying pan" ("как на сковородке"). If that hypothesis is true, I wonder as to exactly what on a frying pan you are figuratively compared to in the second idiom, "like on a frying pan." Or are people are said to be like being fried themselves?
My question: Are there any expert opinions, dictionary entries, or serious evidence regarding the origins of the Russian idiom "like a grass snake on a frying pan"?