inducing euphoria via mild hypoxia is not a good idea. The people touting this in the west mostly don't have the qualifications for doing this practice safely.
It wasn't euphoria. It was the realization that the finest intricate details embedded in the way I breathe, reflect my experiences, and my emotional connection to those details is strongly influenced by what I experienced when I was too young to remember. If anything, the way we breathed -- wouldn't cause hypoxia. Despite years of mindfulness meditation, in which I focused on my breath, that experience changed how I fundamentally relate to my breath.