Ok I got some middle schooler translation on this. Apparently there’s a video of a guy’s (a Half Life character’s) head coming out of a toilet. You can see it drawn on the board to the far right of the picture. In the video, he spouts a bunch of nonsense including “Yes yes”.

Said middle schooler is annoyed that I asked him, since apparently this is some elementary school-aged memes. This checks out, because my 4th grader over heard us talking and yelled “Skibibi!!”