Good old Mommy

Aunt I was in the car with K & D, waiting for their mother to come out of our house.
D: "Where's Mommy?"
I: "She's in the house."
D: "Where's my other Mommy?"
I: "Your other Mommy?"
D: "My old Mommy!"
I: "Your old Mommy? Who's that?"
D: "Bubbie!"

(I reported this conversation to her sister, who said, "Maybe my mother has been spending too much time with my kids...")