we always called them knife hits and i only did them with hash. its when you put 2 knives on a stovetop with the stove on high until the knives get red hot. u break out little pieces of hash like the size of a pencil eraser.

then you get a straw and cut it to abot 3 inches and you touch the hot knife to the bit of hash and it sticks, then you take the other knife and smush it inbetween. this causes it to burn up all at once and u suck the smoke up through the straw or w/e your using. they get you extremely high.