Sorry, this is going to be long and a mess. English is not my first language and I'm a bit nervous.

She accidentaly found out she liked pain and bleeding when she was 19 by using cable ties around her wrists during sex. They dug into her wrists very badly (she had to go to the ER after), but she discovered that it brought her inmense pleasure. She tried bleeding a handful of times, but these times it was by having her back scratched until blood would drip out of the scratches and she tells me she loved it. She hasn't done it since then. She's 33 now.

We started our relationship 6 months ago. I have always been vanilla, but thanks to her I am discovering things about myself that I didn't know. I enjoy certain aspects of BDSM, but what I enjoy most is seeing her enjoy. Up until now, all we have done is slapping her butt and vulva, and bitting (gently) her neck. She absolutely loves it. We have purchased one of those whips with many tails (I forget the name, sorry) and a bdsm set (handcuffs, rope, blindfold...) and we are going to start using it very soon. We are both very excited about that.

Yesterday she told me she would like to explore the limits of her pain. I said I will absolutely do it with her, step by step and slowly. I don't want to permanently mark her, or to have to end up in ER. I talked about scratching her back, because she told me she likes that, but a couple of times I have started doing it and she's asked me to not do that, so I didn't insist. Then she told me why she stops me. She says that she doesn't want to put me through that, because I'm not ready to hurt her that much. She says she absolutely loses control if she feels blood running through her back and even if I stop and ask her to stop, she will get mad at me and probably hurt herself to orgasm.

She was very open about it. So I have thought that maybe that should be our end game. For her to be able to control that. Has anyone gone through something similar? How do you control that? What steps would you recommend we take before we start with the bleeding?

Thanks