(CNN)"You just have to dance, we can make a little money like that."
That's what Shandel, then 13, said her boyfriend told her at a party he had taken her to some 12 years ago.
And that's how it all began, Shandel, now 25, recalled. Gradually, the man she thought of as the only person who loved her or even cared for her, demanded more. Much more -- and she said he would physically abuse her if she refused.
Even now, it is difficult for Shandel -- who requested CNN use only her first name due to privacy concerns -- to talk to strangers about what she was forced to do with men.
She had left an abusive situation at home -- her dad was on drugs, and her mother had "her own issues," Shandel said. The man she left home for "was the first person that felt like who loved me."
"In hindsight, it wasn't love, but it felt like love," she said. "It was like, if I didn't do these things, then he wouldn't love me."
Shandel is among the many victims of child sex trafficking, the commercial sexual exploitation of children. While the term trafficking evokes for many images of children kidnapped off the street, smuggled across borders and moved from place to place, that's rarely the case, social workers and researchers say.
Many who work with the children or who study the problem prefer the the term commercial sexual exploitation of children to trafficking, as it offers a much clearer picture of what's happening.
Most victims know their exploiters
The children most vulnerable are those living in poverty, often known to child protection services, in foster care, in generally unstable conditions, social workers and researchers say. Many have been sexually abused as children before they become victims.
"As much as stories might come out about conspiracies to target people who are relatively safe, relatively less vulnerable, the truth is on the hotline," said Robert Beiser, the strategic initiatives director for sex trafficking at Polaris, which runs the National Human Trafficking Hotline.
"Our data shows that people are exploited because traffickers know that there are certain groups of people that don't have the support, that don't have the ability to get accountability, or justice for themselves," Beiser said. "And those people who, if you exploit them, it's much less likely that any problems will come your way as a trafficker or as a sex buyer."
And the children are far more likely to know, and even be related to their exploiters, than to be grabbed by a stranger, the experts say.
"Hollywood loves a very dramatic abduction and similar stories, but that is not what typically happens in trafficking cases," said Jonathan Todres, a law professor at Georgia State University who focuses on child trafficking.
"It is usually someone they know or someone that an acquaintance knows. So it may be that a peer introduces them to someone who ends up recruiting for a trafficking ring."
Focusing on kids being nabbed by strangers or a child trafficking cabal leads people to miss the point, said Rachel Lloyd, who was trafficked as a teenager and later founded GEMS, a non-profit in New York that helps survivors get their life back on track.
"There are girls who are kidnapped and forced into the life, it's just not the most common," Lloyd, whose organization helps hundreds of girls and young women survivors every year, said.
"It's not stranger danger in the way that we like to think about it. It's about vulnerability and risk meeting the billion-dollar industry, filled with exploitative predators who are, whether they are johns or pimps, looking to continually fill the need