You're not looking to trip but you want to smoke salvia? I'm confused. What I like to do with leaf is smoke bowl after bowl until things start to change. I find it most comfortable to do it laying down, seems to kinda suppress a lot of the uncomfortable pulling and pushing forces.
The only reason you should want to smoke salvia is to trip to be honest, if you're looking to have a fun time it's not going to happen. You might uncontrollably laugh but it's not exactly fun, it's like you're being forced to laugh lol. The first time I broke through I felt like I had discovered something very secret that I shouldn't have known. Like a certain thought that I can think while sober that will send me into this salvia land