Yeah DMT on meth works just fine for me. Do note: I make sure to empty my bladder before I smoke DMT. If I'm on meth, this is especially important. Meth causes some varying degree of urinary retention and this action is almost instantly reversed by DMT. In fact, it can happen so abruptly that I've damn near pissed my pants and flew off to the bathroom in the middle of tripping hyperface, which can be… interesting. One time I experienced the whole sequence of events in reverse, and another time it happen several times over in a row like it was one giant trail. Idk if you ever get stuck in little time loops on DMT, but it's a pretty rad effect.
If I'm really tweeked though I can't seem to break through and I typically will wait until I come down to get into the deemers. You have to remember that meth is somewhat serotonergic in its own way. That's the chief difference between meth and amphetamine/Adderall is that meth has some 10- to 15-times more affinity for 5-HT receptors. Tends to make me a bit scatterbrained.
Oh and there's this certain, idk how to describe it, certain visual effect that I only get from smoking DMT whilst on meth. It's like every object in the room stands to attention and points toward something while it's coming on. Idk, it's hard to describe.
But yeah go for it, I say. I get what people are saying about mixing a psychedelic with a stimulant. Yes, that usually sucks as it's too goddamn anxiogenic – the heart races, skin crawls, and one feels paranoid and uncomfortable. However, this not what happens to me with DMT & meth. DMT is not a typical psychedelic and this seems to make a difference, at least in my case. YMMV of course.