Difrent kid friendly names for vagina?

Ok we call my son's penis a weiner so what the hell can i call a vagina? It has to be a word that we only use for that body part so there can never be any confusion because we are teaching him that no one can touch his weiner not even mommy or daddy. Well he knows that daddy has a weiner and the baby in mommy's belly has one too so he is wondering what mommy has lol I can't think of anything but a vagina and I realy don't want him going around saying it over and over ( he is learning disabled and he gets stuck on words sometimes)