Warning: Sorry, but I have to share this one, even though it's usually considered inappropriate to discuss.
Like clockwork, Riley poops in the evenings between 4 and 6. This week, as he's doing it, he simultaneously tells me that Doak is pooping (our dog). "Mama, Doak poopoo." "No, Riley poopoo," I retort. "No Mama, Doak poopoo." This argument might continue eternally, so I just stop responding with the truth. The first time he did it, he went so far as to RAISE his voice, point his fingers at me, and give a little stomp. (I know, I know--you're wondering where the picture is, right? I don't have one just yet....)
Now, when Riley's telling me that Doak is going potty, I just grab a diaper and some wipes.