i've done the milk thing plenty of times, the first few times it bubbled over and got into the hose, but we adjusted it, and it works fine. it really makes the smoke a lot thicker. I just tried a bunch of times to see how much milk i can put in it each individual hookah that i use. and take care not to smoke it too frequently, so i can let whatever bubbles up pop. But the down side is that it does take away from the flavor a little, not enough to get me to stop doing it though and for those who are thinking of trying it, if you know that there is milk in your hose because of the bubbles, just wash out your hose. you don't want that taste of hookah milk in your mouth, it'll make you vomit.