Immodium AD
I used to like doing speed + weed, but mostly now I just feel the speed and lose the weed high. If you're on any psychadelic (well, any I've tried which is most) weed ENHANCES your trip greatly. Careful though, I've seen people who were enjoying their trips lose their shit once they started smoking weed. Weed topped w/ opium = good. Weed + opiates are good, but I usually just end up in a half-sleep state, with really intense dreams, kinda lucid like.