I have a male friend that cuts.
I asked him about it. He said when he is feeling so bad about something and is not able to help it in any way, it frustrates him. Cutting, or the pain of it, distracts him so he will not dwell on whatever is bothering him so deeply.
He has been trying to stop, but he is an addicted to many things, and Addiction is a hard thing to break.
So I ask him to call me if anything. When he is in that state. He trusts me enough, that he normally will call. I guess you could say, I'm his sponsor. Normally that is someone with the same addiction that is holding strong to their conviction of not using or doing. I'm not in that case. But I am a 12 step user, On bettering myself. Which is the support most people need.
He also needs to know he is a viable person. That can make changes in his or someone Else's life. That the world would be a sadder place without him.