Good question. I don't really do it anymore, but I found that it can provide quite interesting contents. Meetings with entities, and some psychedelic value as well. Quite difficult to work with, yes, but interesting from a psychological point of view. Another reason is that it's very unusual, and effective in whatever the heck it does. It's chemically unlike any other psychedelic. It [salvinorin compunds] carries no nitrogen atoms, and the structure is unintuitive. As a result, it binds into unusual neurons. As a further result, the look and feel of the experience are as weird. It's all quite unusual.
Like I said, I don't do Salvia anymore. It's a bit uncomfortable to do if I use low potency leaf, and I don't have any extract anymore. And on one hand, it's always quite a challenge. While it's interesting and effective, it's also quite heavy material and the usual methods for taking psychedelics don't apply completely to it.
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As I mentioned its psychedelic value, it could be used to meditate on some questions and such, acutely. I noticed I could experience quite a variety of feeling under the influence (but only after I had learned to manage it), but I'm not sure if that capability could be controlled in a real psychedelic intentional session. Perhaps, at least there's some potential. But, for basic recreation, it's too short, intense and uncomfortable. As most drugs are. Perhaps it could boost creativity, working as a kind of muse. Heh, I think most people just do it out of interest, and that very few stick with it too long. I'm not acquainted with the historic rituals involved with its use, or what they wanted to do with it - some sort of healing process, I gather.