Ephedra or Caffeine
I avoided all stimulants for about 6 years, starting when I was 16. Now that I'm 21 and regularly meditating/doing yoga/working out, I've found that a small amount of ephedra and/or caffeine does some amazing things to my meditation process.I find that if I take just a regular dose and then wait half an hour, I can reach amazing levels of disassociation when I begin to meditate. I can stay at these levels for over an hour, and when I come out I'm clearer headed than I've ever felt in my life...of course, the stimulants then make me start shaking and I lose some of the effect, so I'm now experimenting with lower amounts. It seems that I don't go as far into the meditative state on a lower dose, but I feel much better afterward.