You take two knives. Doesn't matter what size, I don't think. I only did it once with two steak knives. You heat them both until they're red hot. Then take a small bit of either bud, hash, keef, or oil (bud works least well) and put it on one of the knives. Smush it with the other until you get a smoke. You can either breathe in straight, or do what I did and cut off the top of a 2-litre bottle and use that to trap and inhale the smoke.