thunder wipies?

Late Sunday afternoon we were getting ready to take Natasha out for Mother's Day dinner, when Evangeline decided to entertain us by dancing to one of her favorite children's songs, which she also performed for us:

Ring arounda rosies
Pocks fulla posies
Wa-shes, wa-shes
All fall down!

Cowsy meadows
Buttie cups!
Thunder wipies,
All stand up!

Thunder wipies?