This is a phrase her father has taught her as a way to instill the concept of sharing. When I first heard it, I thought it was the corniest thing I had ever heard. It sounds like something Barney would say. Then I got used to it and started saying it myself. It worked for the most part.
Well, the other day, DD is eating something she didn’t particularly like. So, she hands is over to her daddy and says in her sweet little voice, “Sharing is caring!” LOL. Boy is she smart!