To gays, and other people! Which experiences had you done with NO2? And all medics here, please, answer me, too!

do you mean

A friend of mine broke his nose doing nitrous. He had two balloons back to back and fell flat on his face.

Are you talking about using Nitrous Oxide gas to get high on? This is the same stuff the dentists use - aka "laughing gas". A few deep breaths of it and you feel a bit buzzed and a little more makes you very drowsy. Pain registers but you are not bothered much by it. The medical systems that deliver it have a safety interlock to make sure you're getting 30 or 40 percent Oxygen. If you aren't getting that much O2 you can die because nitrous cannot sustain life! You can literally smother on nothing but pure nitrous.

In my younger days I have been at parties where a dentist I know had a tank of it set up in the living room and guests could grab the mask, take a few hits, and then float around the party until the effects wore off in a few minutes. The stuff when used at the dentists office works well for me, but leaves me with a headache afterwards for several hours..

It's an "oddball" party drug and it certainly isn't without it's risks. I've known dentists who've jiggered their office unit to supply the gas without oxygen, knocked themselves out and then died breathing straight nitrous in some misguided attempt to get high. Don't screw with it. It, like most drugs, is not without some substantial dangers.

Thank you. Yes, that I meant. But how is it, that it is used in darkrooms, in porno cinemas, and so on, so it is officialy used, I mean.
But maybe, yes, it there some difference between [link to en.wikipedia.org] and poppers and this stuff, dentists use?