What is "toe-curling"

Usage examples of "toe-curling".

As he told long, unfunny jokes, thrummed on the piano, and danced with wonky corpulence, he had become aware that his audience was by no means a captive one, and so began to simulate an even more toe-curling pathos, recounting his long history of failure, telling of previous flops with a forgiving smile, simpering into the microphone about his obesity, lack of rehearsing time, alcoholism, etc.