Losing one's poopetite.
Loosing a poopetite is like loosing an appetite except it affects the desire to expunge one's bowels when seeing something of disgust.
Used in conversation:
A: I thought you said you had to go to the bathroom.
B: I did but I lost my poopetite after I saw the condition of the bathroom in the middle school.
B: I lost my poopetite when the cleaning woman came into the stall and started to mop around the toilet underneath my feet.
B: I lost my poopetite when I realized that the bucket of tissues next to the toilet wasn't garbage from people who had blown their noses.