If doing it alone, the first question would be: How experienced are you with tripping by yourself in general?
Salvia is not like anything else, maybe DMT.. but not cannabis or shrooms. Its onset is fast, it only lasts minutes if smoked.. but can be pretty intense depending on the amount used (what extraction level as well).
Next question: How secure with yourself are you?
Sometimes suppressed memories can surface or things that have been sublimated can come out as metaphorical interpretations much like dreams. However these things might be forgotten once your down or the next day. I actually have many things i know i experience while i'm under salvia as soon as it kicks in, forget when i'm back, and remember again the next time i time i smoke it. The latter things are what i actually bring back, visuals and understandings of what i've experienced.... a certain spirituality of self and realizations of reality.
As for doing it by yourself... Yes a sitter is suggested, especially your first time. However, if you think you can handle it & its a small dose... it might be alright. There are reports of people thrashing around or getting up, but i feel its those that disrespect it and try too much too early. I personally have never used Salvia with anyone else around, but i have used a lot of psychoactives and know myself well enough and what i'm experiencing to comfortably do that. I can also see why someone would want to do it alone, the presence of someone alone could cause anxiety or influence your 'trip'. Maybe have someone in another room, just in case. I've never moved more than my feeling my abs make a weird contracting feeling the first time i used it... i realized i was laughing and didn't know it.
My girlfriend had tried it for the first time a couple of weeks ago, I insisted on being next to her as much as she wanted me there. She sat there quietly for a couple minutes, then a verbal exhale, said "I was not prepared for that" (she has no memory of this). After this she began to ring her arms, from left to right and back again... she rolled over and continued. I assumed something she was experiencing was influencing or a reaction from this. She wasn't able to talk about what had happened for about 15 minutes. Her experience didn't seem monumental to me, but it almost seemed negative to her: Her legs became visible with her eyes closed and felt like they were part of the bed, she felt like she was sliding forward, towards them. They emitted psychedelic light. Her arms tingled with the same light. She remembered seeing my face and had thought i was looking at her and talking... i was quiet the entire time, maybe she was remembering me to help her feel secure. Either way when she came to, she didnt' know she had been ringing her arms either. The next day, she wasn't sure if the experience was positive or negative.... she still wants to try it again, we just haven't gotten around to it. She was apprehensive at first due to a lot of suppressed memories that had always surfaced during trips on acid. This made me wonder how she would react to Salvia, but i also believe you don't always get the trip you want, but the trip you need...
Most recently when i was seeing a folding of perpetual aqua-duct archways fold upon themselves over and in and out and forward and back, all while keeping the archways upright and reflected horizontally below themselves (at each base of each side of an archway was an individual memory btw), i noticed that the horizontal plane began bending, as if the horizon of archways began taking the shape of a rainbow. New archways began blossoming out of this new bend, in between the tops of other archways.... i realized this rainbowing effect was rooted in the fact that my shoulders were in fact raising my chest and back off the bed, like they were trying to touch each other underneath me, it was uncomfortable but i wanted to see what would happen if i continued to allow them to further move towards one another.... the visuals began to dissolve as reality seeped back in. This was the most i had ever moved. I usually lay on my bed in the dark, with no music to influence any visions. I feel that it would cause an undeniable link to consensual reality, something i aim to escape.
I'm not sure if any of this rambling helped, but i hope it gave some insight to your questions...
