Looking for a doujin I found on a few months back. Iirc the plot is something like its the girl's turn to be trained by their gym teacher. It involves a lot of anal, and she gets put on this machine he made that was something like a pommel horse. And it like compresses her poop inside her, yeah i dont even know, and it comes out looking like a black dildo. The poop was nasty but I want to find that artist again because i know he had other non scat work. Was translated in english. Thanks if you have any ideas