If I had an endless supply of nitrous at home, I'd have several best selling novels already, or at the very least, some good columns to submit to various newspapers and magazines, assuming that nitrous use doesn't kill any brain cells.
I always think I'm so sly when I'm hooked up to nitrous. When the hygienist puts that pug nose on me and starts the flow of gas, I start sucking it up my nostrils like a greedy heroine addict. Only I pretend, all nonchalant-like, that I'm barely breathing it in, even though I cannot feel my legs and there is a "whaaawhaaaaawhaaaa" sound rushing through my head. When the hygeniest comes back and asks me if I'm starting to feel it, I try to focus enough to indicate that in fact, I cannot feel it, and with my thumb pointed skyward, gesture to turn the gas up even higher. Which she does. Which results in me getting even higher. YAY!
So the last time I managed to persuade the hygienist into upping my dose (she did, several times, though I'm pretty sure she was on to my wily ways), I was sucking on my mask so hard (I always think that the more deeply and frequently I can breathe the gas in, the better...so I'm basically slow motion nasal hyperventilating, if that's a thing), and was so blown out, that the rubber muzzle thing got suctioned to my nostrils and I couldn't breathe. I started to panic, and I mean panic. I was going to die with a pug mask gripping my nose! And I almost did die, even though there was absolutely nothing blocking or suctioned to my mouth...I was fully capable of taking a breath at any time (again, see photo). I was so high-balls that I literally forgot I had a mouth, which is really stupid since my mouth was the whole reason I was given the opportunity to get so stinking high.
Barely in time to prevent me from my early demise, the dentist came in, took one look at my bugged out eyeballs, and said "You don't have to suck in the gas so hard like that, you can just breathe normally". And she said all this pretty calmly, as if I wasn't sitting there perishing.
Suddenly, a loud gasping sound entered the room as my autonomous reflexes finally took over. I'm pretty sure they turned the gas off after that, because I heard her say "Bring her down", kind of sternly to the hygienist, and that was that.