* Tom walks in on me in the bathroom as I'm wiping my bottom *
Tom: Dad, you have poo hanging from your bum!
Dad: Tom, that's why I'm wiping my bum! Get out of here!
(I wipe vigorously to remove the offending poo before pulling up my undies).
Tom: Ewww, the poo is still there and it's fallen into your pants!
Dad: (I look in my pants). Tom, it's butt fluff for God's sake, not poo. Get out of here!
Clearly my butt fluff is substantial! Rivaled only by my navel fluff.