My children love to play pretend. I am always involved in a minor role in their pretend play. For instance, one might say, "Mommy, pretend I am a baby leopard and you are my mommy leopard." I always respond appropriately, "OK, baby leopard, it's time to practice your leaping."
Then, the leopard will leap away and come back a few minutes later with the next scenario. It might be, "Mommy, now pretend I just saw a lion and I am scared."
Today, my five year old came to me and said, "Mommy, pretend I am your child and you are my mother."
OK, but it'll be a stretch.