Ha! I used to have a co-worker (at Planned Parenthood) whose daughter found a package of pads in the bathroom, and asked what they were. S must have been distracted / in a hurry, and told her "those are for when you're a big girl."

A month later, S was cleaning the daughter's room, and found several pads, paper backing peeled off, stuck to the wall in the closet. When she asked her daughter what they were doing there, the inevitable answer was "well, you're always telling me what a big girl I am now." :)