Body part words

I need some advice/ help. So when my son was learning body parts my MIL and hubby are more geared towards using "the correct terms". So my son has been saying penis since he could talk where I prefer more kid friendly words. Now I am expecting a little girl next month and I've told the hubby we are not going the same route. So when my son starts asking about her privates what words do you guys use? So far if he sees me changing its "mommy's privates" or "mommy doesn't have a penis" haha. Please no rude comments. Growing up my mom called it a coochie, looking for alternatives.