I don’t. In various contexts, the word “sacred” denotes separation between that which is worthy of exaltation and attention, and that which is not. “Sacred” is a form of terminology that derives its meaning from duality; there is no sacred without also the profane. And if we are going to place OM coherently within some kind of historical context of the range of connotations and applications of that term “sacred”, surely OM falls out on the “profane” side. So OM is not a sacred practice, but a profane one.
Alan Watts has this to say about duality – “So in Zen, a duality between a higher self and a lower self is not made. Because if you believe in the higher self, this is a simple trick of the lower self… If you think you have a lower self, or an ego to get rid of, then you fight against it, nothing strengthens the delusion that it exists more than that. So this tremendous schizophrenia in humans beings, of thinking that they are rider and horse, soul in command of body, or will in command of passions – wrestling with them; all that kind of split thinking simply aggravates the problem, and we get more and more split.”
Typically when I have heard the term “sacred” applied to orgasm, there is some kind of hidden neurosis underlying that application – it may be construed as an act of embrace, but it is also an act of schism, of pushing away that which does not meet the criteria. Rejection of the profane, that which is perceived as beneath us.
“Sacredness” is a concept that is very easily hijacked by the prejudiced mind as a way to denounce the feminine. People get killed behind this notion. OM is about the feminine. Even popular notions of divine feminine, which may or may not meet the criteria of “sacredness”, can become coopted with extreme ease into rejection of other forms of feminine. What about the non-divine feminine? I smell a rat; feminine itself needs no additional moniker. It is simply the feminine. The “divine” piece is a cloak which actually bears the mark of the turned-off masculine, once again claiming false authority to deem the feminine worthy or unworthy.