C.H.
You could have your son call you mommy, and your girlfriend Momma (and her first name) sorta like you do with grandma's, like i plan on having my son (once he is born) call my mom Grandma deb, and his dad's mom Grandma paula.
Whatever works for you guys. Good luck! ;-) my email is ____@____.com if you want to talk. my baby isnt due till Jan. 25. 2007, but i know i'm going need some help!!