NSFW Douching nightmare

Okay so i have tried everything in the books to get myself ready for anal but somehow i can't douche to save my life. Literally, no matter what i do or eat, the water never comes out clean, even if i dont put in a lot. Seriously, once i start, it's constantly dirty, no matter how many times i repeat the process. I havent had anal in over a year bc i had a "bad experience" and have been embarrassed ever since and no matter what i do i'm never "clean". Im losing my mind over here. I've read every single douching guide there is but it never works, what am I doing wrong???