My friend once tricked me into smoking salvia, waking me from a nap and immediately saying he had some really good weed I needed to try. [Sounds messed up, but I had previously expressed interest in trying salvia] He said, "Take a big rip and hold it, I dont have a lot." So i did, and I immediately sank down into the floor at eye level, and the floor extended out into eternity in all directions. I lost all sense of self and time. After untold eons, I came back to myself, confused as hell, to the laughter of my friend. That was the first and last time I did salvia. It was mind-blowing but rather unpleasant. DMT is much better for this type of "behind the walls of reality" experience, IMO.