I have reseached and without judging I can say that there´s no method similar to "hitting the light switch" .
There´s no judgment here, research by profesionals like Dr. Nitsche say N is the fastest , painless, recommended way to go.
Euthanasia is performed with it.
I believe searching for a "light switch" method is fantasising and yes it is allowed. No judgment here. If you find a light switch method please share with us. ( with me specially )
With respect, there isn't nearly enough research in cognitive neuroscience, especially regarding the experience of death, to be able to formulate a coherent empirical answer to many of the questions individuals seeking self delivery have. "[F]astest" is relative. For a method requiring someone to wait in a partially conscious state while they are becoming unconscious, there is no necessary 1:1 time association between the individual's cognitive perceptions and time as the rest of us measure it. The perception of time may be dilated while the body is dying, for example.
One justifiably disconcerting aspect of so many lay individuals speculating on methods available to us or relying on the professional opinions of a just a few doctors is the imprecision of external judgments of "painless" -- especially when these judgments aren't scientifically rigorous.
I'm not at all trying to influence anyone else's decisions and I have nothing to gain from anyone choosing (or not) any method. But medicine's understanding of the death process is murky and the nearly universal pro-life cultural bias only exacerbates this by discouraging both scientific research and popular discussion. People are justified in their doubts and attempts to amass even more/better data. And while there may not appear to be a
clearly "instant" method, the assumption that a fraction-of-a-second destruction of most of the brain or key anatomy (like the brainstem) leads to a nearly instant death is corroborated by a history of surgical and emergency medicine literature.
Not trying to be argumentative. If I ever come upon instant-and-painless, I'd share.