Not the fabric ones that you choose to wear in the street now. No. A different kind. The helmet-type ones with sealed, circular glass eye pieces and a screw-on filter. Rubber ones. The ones transformed from a protection from radioactivity to a legitimate fetishwear.
I used to wear masks like that once a week or so. Not for long, for 10 minutes at a time. It was a time when being nuked was a real possibility and it was at school - we were ushered into a room with a lot of instructional and propaganda posters and told to put on the GP-5 mask. I was 7 at the time. I remember the mask pulling my hair in all directions if I messed up the sequence needed to pull a very tight piece of rubber onto your head.
Once the mask was on, breathing was restricted, the vision was compromised, the feeling was claustrophobic.
It definitely was not one of those loose faux-leather masks that are available in every sex shop, at the front, the vanilla section. The seal was tight around my head, the only air I could get was through the filter - it tasted metallic, mixed with the taste of rubber. The sound inside the mask resembled the one of being under water - strangely contained, intensified, interspersed with your own breaths that are so much more audible than normal.
It was a most successful mini sensory deprivation chamber. Every single time I had to talk myself into understanding that the air was still coming in and I can take it off relatively quickly, if I needed to; I can still see a bit, not much, but still. That calmed me down.
The only thing that could not be remedied ever was the rubber edge digging into my neck. It suffocated me, more mentally than physically.
I never complained about it - questioning authority is not my forte, I am more submissive than I am dominant. Being suffocated and not bringing it up as an inconvenience - once a week and at a point where your mind is very susceptible - ends up transforming into an interesting fetish.
I was exposed to this experience again quite recently. My requirement was that the rubber mask be tight, the inside of the filter removed. His requirement was that I wear a latex gimp costume, with a zipper from the top of my pubic hair to the tailbone and a leash. The mask was dark green, faded, the costume was black.