Thought I'd add my two cents here. A few nights ago I came upon some pills containing 2cb and MDxx. I popped two, a low dose for my friends and I, and we all had this amazing, trippy roll party. The evening was conducted as though we were just rolling, only the peak lasted 4 hours. We all were on 2 pills, and all 15 people noted how strong of a roll it was for only two pils.
The extended roll time allowed us to explore our relationships with one another, which took new depth and meaning as we have all known one another for some time.
I was lucky enough to consume a good dose of pure GHB with my pills, and at about 2 and 3 hours in I took small (20-40mg) bumps of K. That blasted the trip off, I don't see how anyone would be taking 200mg plus doses, like a previous poster stated. These hits left me in awe of my surroundings, my life, my friends, my world.
So yeah, my first time with that combo knocked my socks off, but trying the comedown of mdma on some 2cb sounds like fun as well. Personally though, the trip rolling was beyond my previous conception of great, even a solid dose of MDA comes no where near that combo