I experimented with dried salvia leaves last year.
To begin with, smoking the leaves in a water-bong, I found just a wee tingling sensation rising up into my head (like poppers but without the feeling that your head will explode and without an obligitory headache).
The second hit I had was as big as I could fit into my bong cap and my perspective on the room changed, still 3D but angles of the room were distorted.
I continued to take it with similar results....mild hallucinations/visual distortions/tracers etc.
My friend came back from australia and we had an evening in which we took a few big salvia hits from the bong (spaced around 20 minutes apart) and the effects were the same. Then we smoked a few marijuana joints with salvia instead of tobacco, and continued to take hits from the bong. After this we were tripping (my first trip...shrooms came later)....for hours. It was a mild, clean trip with no fear or intensity, but great colours, visual distortions and tracers. If we wanted to properly hallucinate then we'd take another hit from the bond (just salvia) and get 1-2 minutes of the wierdest visuals/thoughts etc, and then go back to a pleasant base-line.
After this I continued to smoke salvia for about a year (from what I had..they were seriously big bags), and each time the trips were getting more and more intense. I believe this is because your body gets more reactive to it, but it could be because there is a technique to smoking it (holding in for as long as possible) which if neglected means that you get nothing from it but a bad taste in the mouth...if you hold it in properly the exhalation actually tastes quite nice, and as your catching your breath your suddenly thrown into a world of wierd!
It does make you sweat but as the trips only last a minute or two its not too bad. By the time you notice your sweating the trips over (and you've stopped sweating).
As I said the trips were getting more and more intense ...i was only smoking dried leaves not extract...and by the end a small hit on the bong was giving me complete hallucinations (the like of which I've not seen since), not distortions but full blown hallucination. In the end this put me off, and after one particular trip I found it too intense and let my friends experiment with what I had left.
Ps. The effect you get from salvia seems to vary wildly, some friends were tripping balls, while others found it did nothing...this could have to do with your smoking technique however it could also be that some people are more susceptible to its effects..If your like me the effects will increase with use.
Definitely smoke it in a water bong cause it is harsh if not (even crush a little ice in their).
PPs. Writing this has brought back a few fond memories, and so I'll probably buy some more come payday, i don't need extract, but because the effects vary from person to person you may.
Happy tripping.
PPPs. it can be intense. Be careful
Smeechdog.