If you get impatient with long stories, even true ones, skip to the second last paragraph herein. That's when I really answer the OP's question
I don't act out medfet. I just like "maskgirl" pics, basically. And bumping into "sick chicks" with masks in public, which is rare.
However, one night, I went to a fundraiser concert for a female friend who was having a lung transplant. It was in essentially a bingo hall in Erie, Pa. This almost didn't happen because the night before, I AIMED my friend, telling her that my apartment tested positive for mold, and I was symptomatic of that. She didn't want to disinvite me, so after some discussion, I proposed I'd get some disposable N95 masks.
The night came, and I was standing outside in the chilly air, and she pops up behind me and asks, in a high, muffled voice if I was that guy who commissioned her from deviantART. I look around and there she is, a thin, 5ft6 brunette, 19 years old, in a dress, big black boots, and a mask. The mask on her mouth and nose at that time was from I Can Breathe, one of those "fashion mask" companies, like VogMask.
http://www.icanbreathe.com
It was white with adjustable earloops and a white lace pattern. I told her I'd be in in a minute; I needed to get my mask on. Mine was a 3M 8210, which is a white cone mask (N95) with two yellow bands. As I followed her in, she had in her right hand the cartridge respirator that I saw her in on her deviantART account. Matte black silicone with huge filter cannisters coming out of each side, capped in white, and a thick black harness dangling from it that would hold it to her face.
So, I got my mask on and we sat and chatted for a while, and the music started. Not sure when exactly, but at some point, she slipped out of her lace I Can Breathe mask and into her bulky, matte black silicone respirator. I didn't get to see her mask up, which is a huge turnon for me, but when she sat down across from me, I just gazed into her eyes and let my eyes drift down from them onto her mask. When she turned her head to a side, you could see the huge mask pressing tightly on her cheeks, being held there by two big black straps, the top one with a cross strap that rested on her head. Tabs were on either side and she did tighten them every so often. When she looked up at someone standing above her, that gave me another view I liked, of her mask sitting tightly on her mouth as my eyes drifted from that interface down her neck and chest.
I'm very sorry this is longwinded. It was just a real turning point in my own sexuality. Having described all this, I was so sure that wearing the mask must have been a turnon for her because she looked so sexy with it on, but as the night wore on, my disposable N95 mask became very, very hot, and it was miserable, and since then, it's hard for me to even get into these mask fantasies of mine, thinking that the girl maybe isn't enjoying it.
I dunno. Any of you wear masks during medfet? Do you like any particular makes/models? Using a cartridge respirator in medfet would be pretty severe. Only a couple hospitals make their patients wear them, and as far as doctors and nurses go, probably only in exceptional scenarios, like the corona virus, and SARS and all that.