Washing my booty

This morning I (Dan) got Lily in the bath. Toward the end she started singing "washing my booty. Washing my booty". I wondered where she heard that but tried not to show it as I washed my hands. I figured it was a 4 year old thing. So i just kind of chuckled to my self. Then she said "hey dad you know what else starts with booty? Booty and the beast. Thats why I can say booty." dont 4 year olds say the cutest things?