Well, I do it because it is the only pain I can control. So much is happening in my life that I am in pain emotionally, and when I get really depressed, my body aches. So then it's kind of just a release of the pain. My boyfriend does it, my best friend, one of my best friends did it, and idk it's just a part of my life now.
It does take away from the numb depressed feeling. There are times when I get in this mood and I don't even realize I'm doing it until after when the burning starts. It's strange, but it works.