Many organizations, as noted by Dictionary.com , provide dates for paying clients, which can sometimes serve as a front for sex work where illegal.
The addition of the word in your query could refer to a few different contexts:
It may refer to an article, essay, or exposé (a "piece") investigating the industry or the people who search for these terms.
It could refer to a specific media piece or documentary discussing the intersection of trans identity and sex work. Definitions and Legal Context