Most of these definitions are wrong.
Real piff AKA piffy
not laced, but grown with opium
in it. Before the plant buds, a syringe is used to inject the choice opiate into it, thus the drug being distributed evenly through the plant. When smoked, the high produced by piff is more of a mellow, relaxed high, then the normal hungry/sleepy/happy/stupid high produced by marijuana alone.
I rolled a blunt with some piff I got from this dude I know, and I was so fucked up all afternoon.