(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)
step on (third-person singular simple present steps on, present participle stepping on, simple past and past participle stepped on)
- Used other than with a figurative or idiomatic meaning: see step, on.
- (recreational drugs, transitive) to adulterate a drug for the purpose of increasing its bulk, and therefore its profit; to dilute, cut.
1994 December 18, NICK LEZARD, “Stepped-On X”, in alt.psychoactives, Usenet:
This seems implausible. If ecstasy is going to be stepped on, you'd dilute it with something cheaper than heroin.