Due to my disability and age, likely, it takes a lot (usually planned) to get me to orgasm, although I certainly have over the years. For me, the most intense arousal comes in the form of my heart rate shooting WAY up suddenly due to visual arousal. The first time I recall that happening, I was 8 or so, and was at a babysitter's house. She had two daughters within a few years of my age.
One night, I was at their house, and being changed fo bed. The lady called out to her daughters to put their pajamas on. A few minutes later, I was helped back out onto the living room couch. They both came out, dressed for bed. The older, taller one, probably 10 or 11 at the time, was blonde and bronzed, and was wearing a pink, one-piece fleece blanket sleeper. The attached booties had the same fleece, except that the soles were made of white vinyl, as were the toecaps.
My heart started pumping very hard as I snuck glances at her. It was hard to hide, and I was too young to understand sex and fetishes and such, so it ttook me years to realize that it was a fetish.
That fetish is ABDL spectrum, not medfet. I do not remember the very first moment my medical mask fetish came to be, I but I was that age or younger. At first, it would excite me to look at a kid's surgery-preparation book and see, among other things, a young girl my age in an OR, lying down, wearing a bouffant cap and having a “black beauty” anesthesia mask pressed to her face.
At some point, that anesthesia mask mostly converted into a fetish for protective masks in the medical context. In general, the heavier the better, but I never liked full gas masks or full mask cartridge respirators; I just prefer the mouth (and secondarily the nose) covered. So, I do like surgical masks (earloop, tie-on or cone), N95''s (3M 1860, 3M 8210, etc), and “EHMR's” (elastomeric half mask respirators) with the facepiece being made of silicone or similar and being held tightly to the mouth and nose by two thick, adjustable straps or one lower strap and a strap harness over the head and ears (Honeywell North 5500, 3m 7500 series or similar). An EHMR would need to be fitted with a filtering cartridge on both sides, which I think adds to the look.
https://www.3m.com/3M/en_US/p/d/v000057591/
I will say some EHMR's (which are sometimes black) kind of remind me of those "black beauty anesthesia masks, but with straps and huge filters.