Let's trade!

So we were at Burger King tonight for dinner (how we got there a totally different story). We were waiting for our food and Luke was drinking his water. He asked what I was drinking. "A milkshake", I replied. He wanted to try it so I let him. He looked at me and said, "let's trade" and shoved his ice water my way. He sat drinking facing me for a few seconds then thought better and turned so his back was to me. I couldn't help but crack up.