Probably for the smell.... Make sure you use a separate bowl and regularly change the screen
There's the metal oil smoking screens they sell, but I imagine a heath stone or whatever they are called will probably works best or even that on top of the mesh screen to make sure the dmt doesn't drip into the volcano itself.
I've heard it works well especially when you want to get multiple going at once, but I don't know temps that you'd have to research. I'd recommend asking this at the dmt Nexus or in the science discussion area of the board.