Tracy Quan is the author of the novel "Diary of a Manhattan Call Girl" and a contributor to "NYC Sex: How New York City Transformed Sex in America." Working at a peep show isn’t as easy as it looks.

Turf, a contortionist dancer who took his act from the streets of San Francisco to Las Vegas and, finally, the stage of NJPAC for "America's Got Talent," delivered a show-stopping performance Tuesday ...