As others have pointed out repeatedly, med-fetish calls for a vivid imagination, and a strong sense of trust between the principle players. For me the idea of undergoing the process of being prepped realistically for "surgery" is hugely appealing (although I have not experienced it personally). The idea of presenting oneself at the appointed hour, completing paperwork, being stripped and examined, prepped and draped, etc. is an enormous turn-on.
Again, it is the surrender of control that is so thrilling, and the idea that one is at the mercy of others who have an agenda for you. I find the idea of being stripped and prepped in front of several individuals (the surgeon, the anesthetist, and assorted nurses and assistants) in a lighted surgical amphitheatre, to be particularly titillating!
The only real surgery I have experienced occurred when I was a small child, but I vividly remember that the day I presented for the operation I had a cold -- so I had to undergo the preparations twice -- blood tests, rectal temperature, physical examination, etc. It was only when the surgeon walked in for the final exam before being carted into the operating room, that the cold was discovered and pronounced disqualifying as far as the procedure was concerned. My parents took me home, and we had to come back two weeks later and go through the whole rigmarole a second time. This time I was pronounced fit, and the surgery was performed.
I remember three aspects of that experience with extreme clarity. The first was the visit of the pre-op nurse at my bedside, with my mom and dad in attendance, who pronounced that it was time for me to receive my shots -- two injections (one in each butt cheek) which would send me into surgery on a drug induced cloud of haze. I hated shots as a kid, but somehow I knew that I had to be a "big boy" for this experience, and so I remember turning over in the bed and enduring two "mosquito bites" without much complaint.
The second part of the experience I recall was moving from the bed to the gurney (sore bottom and all) and my parents walking with us as far as the door to the operating suites. They had to leave me there, where I was confronted by the scary aspect of being surrounded by a number of figures clothed from head to toe in surgical gowns, caps and masks. This was long before the kid-friendly surgical procedures of today -- and was a very frightening experience for a kid like me.
Finally, I remember the black mask the anesthetist fitted over my nose and mouth, asking me to breathe deeply a foul smelling gas which put me out. "Count backward from ten," he said -- but I don't think I made it past eight!
It would really be something to relive those experiences (absent the postoperative experience of waking up sick to my stomach and in pain), among a group of trusted friends in a role play experience. Thanks for getting me thinking about a great fantasy script possibility.