contrary to a "shameless shitter" a shameful shitter will hold it in for hours before daring to go into a public restroom, they rather wait 'till they get home or in a case of an emergency they will scout out a lonesome or retreated restroom and proceed to shit and run, but they will do it in a continued state of terror and anxiety that someone will come in and smell their aroma or hear their farts, in such case they will wait for hours until the restroom is clear of people to avoid the "Walk of Shame"
Wife : Honey can't you go any faster? I'm prairie dogging!!
Husband : Why didn't you go at the mall?
Wife : The restroom was full and you know I'm a shameful shitter, now step on it!!