When the frog passes feces it is coated in a soft, slimy mucous like coating, like most animals. The excrement at that point is soft and any undigested particles are mixed within the soft stool, making it easy to pass.

Yes....I am very aware as I am also a med/surg nurse and deal with similar human issues nearly everyday.

Varying the diet creates the best 'consistency' of stool and provides the best nutrients.