The first time I took booms was a few years back. The who's, where's and when's aren't really important. I took a little over an eight to myself. I don't remember much of what was going on through my head. But the most mind-opening experience happened. Every memory I could recall, I could see it and experience it from everyone's perspective in that memory, but I couldn't figure out who's perspective was my own. Example of memory; 3 people sitting around a table, one cracks a mean but really funny joke on the other. I saw it from the Joker's mind, the victims eyes, and the observers perspective. It got to the point where I was laying behind a couch probing my face with my fingers trying to remember what exactly I looked like. And that's when the idea of how we're not our looks smashed me in the face. Scary at the time, but a great experience to have had.
I also recommend watching Fear and Loathing in Las Vegas tripping. You can't go wrong.