If you are referring to the advanced barrage that stops at the top or bottom of the center of the screen and has color.

First of all, you must be a formal member. Open a video screen and click the third button on the lower right to launch the barrage. Then you can select the position on the screen (the upper button) and click the last ">" button on the right. You can select the color of the barrage. After typing, click to send the barrage. The barrage you sent will be framed in a green box.

Other cool comments have to be sent through a computer and seem to require the approval of the up owner.