... but that doesn't mean I was prepared for it. Thankfully because of God's grace, I was able to respond well.
Lucy came down from her nap one day, after spending some time in the bathroom (which isn't uncommon - usually she gets dressed and takes a bathroom break before coming down) with makeup "on" and all 20 of her digits (along with parts of her legs and arms) painted with grey fingernail polish.
We had never had a talk with Lucy about not messing in my makeup bag or using nail polish alone, without asking first. So, she and I had that talk as I helped her clean up. We washed her face, I removed all the polish from her finger nails, hands, arms and legs and then worked on cleaning up her pedicure - she had grey toenails for a little while which served as a good conversation piece and reminder that next time: we need to ask. :)
The next day, she asked if we could paint her fingernails pink and we did.
It was a good experience for me as a mom. One of the rare moments I think I correctly assessed the situation and helped with clean up but decided that discipline wasn't necessary. She didn't get fingernail polish on the toilet, floor and sink on purpose, didn't wreck my eyeshadow and lipstick maliciously and didn't go about painting her nails in a secretive manner. She just wanted to look pretty and be like mommy by putting on make up and painting her own nails. I saw my little girl as a little girl, who is 3 and makes mistakes. It was a humbling moment as a mom and an interaction I will not soon forget.