step on

step on (third-person singular simple present steps on, present participle stepping on, simple past and past participle stepped on)

1. Used other than with a figurative or idiomatic meaning: see step,‎ on.
2. (recreational drugs, transitive) to dilute, to 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.

• netops, pontes, posnet, septon