Not really true, I'm afraid. or at least, certainly not proven.
Endogenous DMT is present in minute amounts in the body and is being researched, but I am not aware of any link with death, nor of concentrations any where near close enough to create an hallucinatory experience.
There is an interesting, but rather dated, paper on the relation between hallucinogens and substances occurring in schizophrenia etc. here:
http://schizophreniabulletin.oxfordjournals.org/content/2/1/90.full.pdf
Sorry if all this seems less magical but the mawkishness of that jpg set me off on one.
...and whilst we're on a bad science tip - the idea of pronouncing a sound which is a bilabial nasal without using both lips is foolish. It's like saying, "Try punching someone without using your hands".
OK - got that out of my system... carry on chaps.
