i've done it, i've only seen really poor people do it though since they had nothing else to smoke out of(not saying that ya'll are poor, i'm just sayin, u know). Anyway, I dont use the bottle technique since it makes it taste kinda funny to me, i just press the weed together with the hot knives and put the tip of the straw as close to it as i can and suck real hard to get as much smoke as i can.