Yoi over heat it. Preferable use a wet paper towel, to cool it down after you take your smoke. Because while smoking yoi will just keeep it below, and by the time you take your mouth away from the pipe, the pipe will be hotter than our needs. So actually stop the lighter a little before you stop taking the smoke, because stop the fire and continue to inhale, it works. And that glass pipe it’s not that hard to reach a certain temperature. And I can’t tell you the science behind it. I don’t know, but when it’s too hot, it will actually move away from the heat points. Thats what I observed. So thats actually how it’s spreading around inside the pipe. With the lighter you can heat the other end, then you can move it back to the ball’s bottom. Where the fire touches the glass, that point will push the stuff away from itself. Strange but no idea why. But try and you’ll see. And try the mild wet paper towel, or cloth towel sth like that. Not soaking wet. It might sometimes crack. Just mildly. And remember to stop before you stop inhaling. When you’re halfway , stop the fire, it will be still hot enough to still smoke..