Little kids are often instructed to substitute "Diarrhea" with "The D Word" e.g. "Mommy, I have The D Word." To avoid any negative consequences that come with saying "Diarrhea". Especial when onebhas guests or are in public.
This is the type of question you ask skidiots to check if they really are as stupid as you think they are.
Normally used when talking with someone that acts as if they know what they are talking about but truly has little to no knowledge of the subject, normally used when talking to people about cheats or scripts.