An A's A.

So there I was with my son in the public library parking lot (not that the location matters, but I have to wonder where and why and how he comes up with this stuff) when we engage in a conversation that goes basically like this:

Son: "Dad, remember back when donkeys used to be called the 'A-word'?"

me:"Ummm... yes?  But you can still call the donkey 'the A-word', you know."

son:"But it's not nice to say the A-word."

me:"Okay."

son:"Then what do you call a donkey's behind?"

me:"Ummm... maybe a donkey's behind??"

son:"No!  You call it the A's A!  hahaha."

I guess it's comforting to know I have a fairly normal fourth grade boy...