Hi Kyi, The black stuff is like shrinkwrap, it is there so that know juice seeps into it at the top of the tube that is connected to the ceramic cup. Ok when you take the drip tip off you need to look down into it, you see the clear plastic peice that has the hole were you put the needle in for filling with juice. What Bad is saying is to remove that plastic clear piece, look at it, on the bottom there are two little V like slits. Those slits are supposed to be put over the exact area of the wicks in the carto when you are putting it back together. What he is saying to do is instead of putting it back in that way, put it back without lining it up with the wicks. This should seal it better so that your wick near the coil is not getting to much juice on it which is the cause of your gurgling. The ceramic cup is the white piece that the coil is siiting across with your wicks going out the two sides where there are small slits in the cup. I hope This makes some sense, I know how confusing it was for me when I was new to vaping. I had know Idea what everyone was talking about lol, but after alot of time spent on this forum with so many people here willing to help with any questions and doing alot of reading and research you will understand most of it in know time.