Why is it sill there?

Conversations with Emily have always been adorable, and no more so then the one I had with her Friday night:

(a little background- I have three small stars tattooed on my right foot. Emily has seen them many many times before, she usually just points at them and says "stars" at which point I say "yes, those are stars" the end)

Emily: "Why is it still there?" (pointing at my tattoo)

Me: "Emily, those are always there"

Emily: "But why? Mine come off."

Me: "Mine are permanent, they stay on all the time, no matter how much I wash them."

Emily: "Sometimes, I have tattoos, here or here (pointing at her arm, and leg) but then I rub them, and they come off."

Me: "Yeah I think your Mom likes it that way."