A friend heard this phrase in an episode of Masterpiece Theater and had to Google it. It includes one of the four-letter words I don't usually include in my stitching vocabulary. CAUC stands for "Complete And Utter C*nt". Oh dear. How not quaint. I'm not sure on what occasion this would be appropriate. Maybe you could make up your own fake definition in case anyone asks, like Congratulations, Aren't U Cute or something tamer.