Ticklish

Today, during circle time, I noticed two girls in the back being giggly and extra disruptive. I look up from the book that I was reading out loud to the class and saw that both of them had their legs raised in the air with their hands inside their panties. Resisting the F-bomb, I tell them that their actions are inappropriate and that they should go wash their hands. What do they respond to me? "This tickles my peepee."