I'm not ready for these conversations

Right before rest time today this was Isaac and my conversation:

I:  Momma, where does our pee come from?
Me:  What??
I:  Where does our pee come from?
Me:  Well, when we drink fluids like water and milk our body uses what it needs and then our bladder holds what we don't need until we pee it out. 
I:  What's a bladder?
Me:  It's the part of our body that holds the fluids we don't need. 
I:  Oh.  Is that what those balls are in my underwear?
Me:  WHAT!?
I:  I have those things that are like balls in my underwear...is that my bladder that holds the pee? 
Me:  Um, no. 
I:  What are those then?
Me:  Um.  Ok.  Those are called testicles. 
I:  Testicles? 
Me:  Yes. 
I:  What are testicles? 
(Oh sweet mother of mercy do I really have to have this conversation.  Why oh why isn't their father ever around in moments like these???)
Me:  {Big sigh} Your testicles are a part of your body that will someday help you have a baby with your wife. 
I:  What is a wife??
Me:  Your wife is the woman you are married to.  I am daddy's wife. 
I:  I'm a boy!!!  Boys don't have babies!!
Me:  I know that, son, but it takes a man and a woman to have a baby. 

{HOLDING BREATH}

I:  Ok. 
My only thought:  Thank you, sweet Jesus, that's the end of that conversation.  For now.  I know Isaac far too well to assume that's the end of it.  But, it appears he might be going to see Poppa and Mimi for some special time.  One can only hope he'll want to continue that conversation with them...