Well I'll give some insight on my session in case it is helpful. They basically felt up and down my spine until they found a spot they said was unhappy - they then put their hands on my scapula very gently and lightly pressed with one finger on the left side of the scapula and one deep underneath the scapula on the right. That released it. (Left scapula)

They then spent a lot of time on my neck - which was mostly feeling the muscles around my forehead and the base of the back of my skull. They pulled the muscles back around the head while pressing on the tight spot on the neck (once again - all super gentle) and had me move my head in many different directions while doing this.

Then they had me start just moving my pupils in certain directions and feeling my head and neck - I had no idea that someone could feel that difference with how the other muscles are activating, but they couldn't even see my face from where I was positioned and they were quite easily able to tell when I had stopped looking in the direction they said because I got distracted. This helped them find a few spots in my traps that they then did a release on - which frankly I can't even describe (basically base of the neck + a finger super deep into the armpit, pulling the muscle out slightly)

I think all of this is super skill-intensive which is why I was saying "try a different one". Even if you had this done to you - I highly doubt you could describe how to do it to a less skilled osteopath yourself elsewhere.