1. Substance D is a fictional addictive amphetamine-like psychoactive drug, also known as "Slow Death", "Death" and "D", that is depicted in Philip K. Dick's novel "A Scanner Darkly". It's derived from the fictional flower "Mors ontologica".
2. By extension, Substance D can refer to amphetamine (speed).
"What he sold me as 'candy' actually turned out to be 'Substance D'."
When a woman in the age gap, 24 - 46 snorts cocaine (or other snortable illicit substances, including sherbet) through a a straw inserted into her vagina hole. This procedure must tke place, in humid conditions, between the times, 2:45am and 3:32am.