-You are overestimating the amount of shit produced in one siting XD. Also, I you get yourself dirty is YOUR shame, so more interest in keeping yourself clean. -You don’t have to go that deep. Also, using a stick to clean your ass is very uncomfortable, one should expect that the romans would have found a better way in all its story.
P.S. I love being able to discus how people in ancient times wiped them selves.
And why should I go that deep? There was running water. You could perfectly clean the dirty areas who could touch the next person using the toilet. And then use running water or other solution to clean yourself. Also, we don’t know if there was also wood in the toilets that didn’t survive thousands of years.