I have had thoughts recently about bdsm and violence, but I put myself in the victim role.
I made myself really dig through why it is that I had these fantasies.

It was difficult and upsetting, but I feel clearer now, and I don't have those thoughts in the same way at all. Whilst it's okay, of course, to have fantasies as long as we never act on them, and can stay in control of that, I personally feel that it's not a healthy or kind thing to do to yourself.

It's interesting that you talk about being in control..might be that you are compensating for times when you have not had control in your life? It's probably a good idea to talk to a therapist about this stuff, one who accepts this issue and will be open and able to really go there....