Mermaid Girl on Fairness

Me: Wow, look at your nails. We need to give you a manicure.
MG: Don't touch me!
Me: How can I not touch you? You're sitting on my lap!
MG: Okay, you are touching me. But don't touch my fingers! Or my toes.
Me: Can I touch my own toes?
MG: It will be hard, because I'm sitting on your lap!
Me: [touching my toes] Ha! I did it anyway!
MG: [grabs my big toe]
Me: Hey, how come you get to touch my toes but I don't get to touch your toes?
MG [grinning wickedly]: That's...the way...the world goes!