I used to make this noise all the time, I called it the dope groan, it’s our bodies’ mechanism of forcing ourself to continue breathing, and with that, that means we’re veering much to close to the line. It’s difficult, with my experience, to cast much judgement as that was typically my goal state to reach and I fear many opioid addicts‘ ideal state. Eventually, you will undoubtedly cross the line in the spectrum where your body is unable to allow you to continue to breathe, and once that threshold is reached, there is no guarantee you will ever experience one more second of life on this planet.
By the way, once you cross that threshold, there is no guarantee you will be completely unconscious and painless, your brain will start misfiring due to lack of oxygen and the experiences at that point, in my experience, are incredibly painful and terrifying.