Question for the Hookah Smokers

I've got buddies that go to the Hookah lounges, and they all tell me that it depends on what you smoke that'll burn your throat or not, as well as how big of hits you are taking, you don't want to over-do it because they can dry your throat out as well.

Well, for instance, yesterday I smoked a bit of a flavor called double apple. It was great. Then I put a new coal on top, and all of a sudden it started burning like a bitch.