If you want to feel narcosis, substitute argon for nitrogen in the mix (while obviously keeping the same oxygen content in the breathing gas). It's 2.3 times more narcotic than nitrogen. :shocked2: That should get you good and narced.
I have always thought this would be a safer way to teach narcosis management, but nobody ever takes me seriously.
Controlled experiment? Do some math and dexterity tests. Time on the surface and have buddy time you at the bottom.
This was really brought home to me when I was doing some deep dives and trying to mentally convert PSI into Bar. Very easy at the surface. Much, much harder at 130 feet.