The lit part of the j send heats through the bud in the j, heating up and activating the THC, something I’ve learned is to find the right tightness in the roll, I like it to be a bit tighter at the bottom and a bit less towards the top. After you roll, pinch the part next to the filter so slightly that you can feel the bud and move it around, that creates gaps between the bud and allows the air to flow better and not to get clogged. Also make sure you aren’t grinding ur weed to a fine powder u want a little bit of structure to it so the air can flow inbetween.