L.S.
My daughter used to come and show me her bottom to make sure it was clean....
My brother who has no kids and does not deal with little girls.... came running to the bottom of the steps one day when he heard her yelling at the top of her lungs, only to find her bent over with her cheeks spread asking him "am I clean?" maybe it won't help you, but I thought it was funny enough a story to share and let you know that this is a normal thing.
Enjoy!