i know a lot of people have put ice cubes in bongs before. i've done it myself and it's pretty fucking cool. the smoke is nice and cold and smooth. well my friend and i decided one day what it would be like to put hot water in a bong. neither one of us have ever heard of that being done before so what the hell we gave it of whirl. and wow! it was superb! we thought that it was almost as smooth or even smoother then using ice. so if you want to try something new, try it!