Dirty Love - The Mothers of Invention
Can't go wrong with this one. It's by FZ & The Mothers and it mentions mothers in it. It's even SFW (though it's suggestive as hell).
Open That Can - Nancy White
I know you were the last to play this (last August), but this is one of the most upbeat "mother perspective" songs there is.
To Mommy - Barry Louis Polisar
The sort of Mother's Day song I'd play if I had the energy. SFW.