“If you want to make some serious money, we require a full-body photograph,” a shadowy online recruiter who purports to offer a lucrative side job at a massage parlor offering sex services tells Christina, a 22-year-old exchange student, over Kakao Talk — South Korea’s ubiquitous mobile messenger app.

“The associates who cater to our VIP clientele can earn upwards of $1,154 (1.5 million won) a night. Our clients are primarily executives, so they’re often generous with tips.”