WCguy's post made me realize that I had forgotten about this with 2 of my cystos. You're absolutely right about it being comfortable and more revealing/embarrassing/enjoyable.
With one of my cystos, the female nurse stepped out while I undressed and got in the chair, then came back and just quickly put the betadine on my penis with a cotton ball, squirted in the lidocane, and then left and let the doctor do the cysto.
With the second one was with a different urologist (both urologists were male unfortunately)it was much more enjoyable.
The nurse led me into the room, and while staying in the room told me to go ahead and take everything off from the waist down. Then she helped me climb up into the chair and place my feet up in the supports, then told me to scoot myself down lower in the chair until my backside was hanging over the edge. Then she went about the prep of cleaning and numbing with the betadine and lidocaine, but this time it was more fun because she joked about the fact that she kept the betadine chilled, and I joked about how if nervousness didn't shrivel me up, her freezing me would. I really liked that making jokes about my penis was just a casual thing.
After she prepped me, she said "we'll be back in a few minutes" which made me wonder if she was going to observe the cysto. Sure enough she came back with the doctor, so while he was doing his work I just looked at her, enjoying the fact that her gaze was locked on my genitals the whole time. It got even better though because he had her take a look in the scope. It really added to my humilliation/enjoyment to not only be laying there in the gyno position, having her stare at my genitals, but now she was even looking INSIDE my bladder.
After it was done, she stayed in the room with me while I cleaned up and got dressed. she handed me some baby wipes to wipe the gel and betadine off while she tidied up the instruments. We talked while this was going on, and it added to the enjoyment by having her glance over while I'm wiping my penis and testicles, and she even commented that it gets kind of messy with the betadine and stuff.
For someone with a med fetish, I'm not sure how it could have been any more enjoyable, other than maybe having a class of 20 med students observing as well..... but I never get that lucky.