I have to say, Marbas is one of my favorite spirits to work with when it comes to teaching healing/poison!
He and I made a working pact together, and so far this technique has worked wonders for both rapidly healing myself of a cold, as well as menstrual pain (And I mean severe pain, to the point of not being able to walk properly)
What I do is go into a light trance and visualize his sigil on the afflicted area. Then I visualize (sometimes I just emotionally feel, instead of focusing on color, it’s easier at times) a dark brown (I use this for pain) or grey or sickly yellow (yellow is usually for viruses in my opinion) entering his sigil, and stating to him that I sacrifice and let go of the illness/nausea/pain what ever the problem is…
I do this while doing slow breathing, which seemed to be enough to bring me into a light trance…
As an added bonus I had Paimon influence the energy to leave and detach, which seemed to make the whole process happen faster.
Now for the last part. Paimon is excellent about teaching about the mind… And he taught me that the mind isnt just in the brain or in the head, each individual organ seems to have its own form of a “mind”, especially in the stomach reason (Maybe how intuition is sometimes called a “gut feeling”?)… And that sometimes pain and illness originate from too much of a disconnect from the mind of that organ… In this case he showed me that I was severely disconnected from the mind of my womb…
One thing that I love about the demons is they not only do what you ask, but they also teach you how these things work and how to do them yourself!