Not ready for this discussion

Princess came home from a friends house the other day and informed me that all girls had eggs in them which would become babies. I said yep thats right- and I reminded her of how her siblings grew in my tummy and came out. She me took it a step further and remembered that there was a girl part and a boy part that came together to make a baby.

At this point I was feeling so good about my handling of the situation. I should have taken more care not breaking my arm to pat myself on the back. Because no sooner had I taken a breath of relief did she follow up with a really great question. "what is the boy part called?" and "how does the boy part get inside the mama?" hmm well. hmm. I darn naear choked as that was not what I expected to disc

When I was pregnant with Stinky she was very afraid of him being born covered in - exucuse me- poop. She was relieved to learn that there was a special place in mama's that kept them from getting all messy in that sense. Somehow I did not think that this question would be handled with that kind of ease. So I told her I had to think about the right way to explain it and we would talk about it later- so far she has not asked again..

What am I supposed to say??