Hello! I have three suggestions.
1.) Make sure you are printing at 100% infill
2.) If you are using PLA, try instead PETG
3.) Your clay body may also be the culprit. Experiment with different clays at different dilutions. I like to put a bit of clay in a 60 ML syringe and test how hard it is to extrude. If I cant extrude it by hand, its unlikely this 3d printed extruder will be able to either.
Bryan