"When I was 13 I hadn't even started puberty. I looked like a ten-year-old" he says to Swedish Radio.
Niklas says that the pain of being abused was soothed by selling sex
"It was so easy to do it and it it felt so good," he says, adding that it was like a big lump in him, that only loosened every time he was paid for sex.
Mikis Kanakaris is the head of "100 possibilities", an organization that helps young boys to start a new life. He says that becoming a child prostitute is a kind of self-harming behavior, and that some react to abuse in this way, while others may start cutting themselves.
"If you have been abused you might deal with the pain by re-living the attack and so trying to take control over the re-lived situation" says Mikis Kanakaris.
Young boys have to trouble finding older men who want to buy their services. At least, until they reach 15, says Mikis Kanakaris.
He thinks that lots of boys don't dare to show weakness and admit what they are going through. But he adds that it is important that they know they are not alone. "There are, unfortunately, many more. But there is help and support" he says to Swedish Radio P3.