I've done that, on several occasions, also in combination with oral caapi or rue. Also with a layer of freebase underneath the changa. Actually it's only an 18" bong but I also do a lot more than 2 rips in a row. Unless "God" looks like some vague colored squares and stripes, I can't say I've met the fellow.

So I can totally relate to Global's friend, sounds very much like my own experiences in this area. People are very quick to jump to the conclusion that there must be something wrong with the device or the technique, and I can understand having that opinion when just a few hits is enough for them. And the vast majority of the time, they are probably right. But when you've smoked your way through a few grams using all the advice given by the experts here and every possible vaping/changa/MAOI combination, way beyond the usual recommended doses, and still don't get much but some vague abstract color patterns and a "trippy feeling", it's pretty hard to listen to the opinions of those who weren't there, and don't know firsthand how hard you've tried.

I wouldn't say I'm totally "immune", I do get effects, sometimes strong ones when I combine an oral MAOI with multiple bowls of changa and/or freebase. But with one or two minor exceptions these experiences have been totally non visual, just like I've never had any visuals on mushrooms but still feel definite effects from them. It seems to only be the tryptamines that work this way, since I used to get very strong visuals from LSD. I haven't tried mescaline yet but I'm quite curious what that might do.

I actually get a lot out of these experiments, they just don't do for me what others say they are "supposed" to, and it's a lot more work to get there. So while I don't intend to stop trying, at this point I'm forced to consider the possibility that my breakthrough threshold really might just be beyond what is possible for me to consume. I've just recently made a 100g caapi/100g chacruna aya brew, we'll see how much farther that gets me than 50/50 brew did, which was about the same as an eighth of shrooms (fairly mild, still functioning pretty much normally, and a little bored.)