Had to laugh at that. My last dog would milk an old minor injury to her leg. One time that I got a little mad at her she sat down and held up her foot. I looked at her and said ”Wrong leg,” and she changed to the other one.
Tito the Wonder Dobe had a sharp stick poke him in his hind leg out in the woods and after it was removed [YEARS after, long and completely healed] any time he was in trouble, up came that leg with the big sad eyes.
It always worked on me.