Where's Your Diaper?!

Lucy kept taking her pants off today. She would take them off and I would put them back on. Finally I realized she was taking them off because they were falling off. So the next time she shimmied out of her pants I let them stay off. A few minutes later I was in my bedroom talking to my sister on the phone when Lucy climbed up on the bed to sit by me. Being a little distracted it took me a few minutes to realize that she was not only missing her pants but her diaper as well! Then I noticed the front of her shirt was wet. I immediatly went into action. Luckily I didn't have to search too far for her diaper. It was in the hallway outside my bedroom door, nice and clean, laying next to a big puddle of pee. I quickly got the situation resolved, pee cleaned up, dirty shirt off, diaper back on, everyone happy. Everyone was happy and laughing. What were they laughing at? The boys were laughing at Lucy running and Lucy was laughing because the boys were laughing. Then I started laughing. As Lucy was running one side of her diaper came undone, unable to stand alone the other side slid right down her leg. Without missing a step Lucy simply stepped out of her diaper and kept running...