I have. I still do. I love the sensation that comes along with it, as long as it doesn't last to long. Then it is just disorienting and I feel like I am falling through space, without a concrete sense of direction. It only scares me if it lasts too long and I can't grab onto something more solid and stabilizing.
When it happens I lose my sense of time for a moment or two. I feel like I am all of it, and it makes my head spin, because I am all of it and outside of it looking at it from a perspective I cannot put into words. I love it.
Edit: It happens without drugs too.