"Will Rogers" second chance
Refers to the rare and off-the-scale-wonderful "lucky break" obtained in the following scenario: you are "just suffering" to say something rude/impolite, but then of course you immediately regret said verbal-indiscretion just as soon as it's slipped past yer flapper. But then --- by the grace of Fate --- the unwitting recipient of your snide remark either hadn't been paying attention properly when you'd uttered your auditory barb, he is a bit hard-of-hearing, or you hadn't been speaking loudly enough to be heard over the distance and/or other background noises that were present at the time, and so your "victim" never actually understood --- nor did he suffer any emotional distress from --- your insult, and so he innocently/apologetically asks you to repeat yourself. But of course, YOU DON'T ACTUALLY HAVE TO SAY THE MEAN STATEMENT A SECOND TIME --- now that you've "relieved your internal pressure" by initially making the simmery-tempered remark and then THINKING that the other person heard you, you can now proceed more clear-headedly, and so you can simply say, "Nuthin'" or, "Never mind" when the other person asks you what you'd said.
I was heatedly peeved about how long it had taken the local garage to repair my car, so I made a regrettably-choice remark as I entered the office to pay my bill. Fortunately, though, the office's connecting-door was still somewhat ajar as I spoke, and so the din of the noisy garage-tools drowned out my derogatory statement, allowing me a classic "Will Rogers" second chance to just clamp my tongue. Yup, Ol' "Willie R" was right --- "Never miss a good chance to SHUT UP."