I wrote a cat book in English and am translating it into German right now (native German) but I can’t find a real good word for poop.
Häufchen, literally "little heap", it is what cat droppings are often referred to.
It is a naturally harmless and polite expression, so there's no danger of being rude. However, it is not very funny either.
P.S. "Häufchen" is usually not used to express dissatisfaction in the way "poop" often is. I guess it would be understood if someone did, and it would be kind of funny too.
Examples for proper usage have been posted as comment. I'm not putting them in my answer in order to avoid stealing the comment's votes. Thanks for the support, Phil.
Growing up in a German-speaking family, I've encountered various terms that at least by ear sound related to "poop":
- "Puh, das stinkt hier!"
- Puh-puh machen (small child talk for going to the toilet for "number 2")
- ... and then you get Pupsen, Pupse, Pupser which is related to farting. (The dictionary suggests to this non-expert that the original meaning of poop, silently breaking wind, was carried over (perhaps as euphemism) for passing wind (farting) and then to the passing of excreta. So perhaps wind-related terms would not be what you are looking for, or perhaps you could make it work.)
- So perhaps something made-up like "pupu/puhpuh" would work for you. (It's unfortunate that in other languages words like Pupu Kaka make quite normal and honorable names.)
As a expat German in another culture, it's hard for me to tell how widespread these would be understood.
Relating to pets, we would usually use the words "Mist", "Kot" or "Dreck". Fairly factual, with the connotation of "dirty, stay clear". Not really any cute sentimentality to it.
I guess it's interesting that other germanic languages also have similar-sounding words ("poep" in Dutch, pronounced like "poop") with the same meaning. So I guess its not a recent word.