There was once a boy who would never get dressed when his parents told him to, nor would he put on what they wanted him to after his bath. He preferred to dress in a much stranger manner, but above all, he liked to take his time. His parents were always in a rush, and wanted him to be a lot quicker, but the boy didn't like this, and he would slow down even more. One day, his parents were in their usual hurry, and they got so angry when he refused to dress, that they told him that he would have to go out naked. The boy didn't mind this in the least. So out they went. While the boy was standing naked outside his house, waiting for his parents to bring the car, along came the local pig farmer. The pig farmer was hard of hearing and had poor eyesight. Not only that, but he'd also forgotten to put his glasses on that day. When he saw the little boy's pink skin, he thought it was one of his pigs. And, with a bit of shouting, prodding, and pushing, the farmer managed to get the boy safely back to a pigsty. The boy protested the whole way there, but as the farmer was almost deaf, his complaints didn't help him. And there he was for the whole day, living amongst the pigs, thought to be a pig, and sharing their food and home. Finally, though, his parents found him. The boy had had such a regrettable day that never again did he want to be mistaken for anything other than a human being. Nowadays he's the first to get dressed, and look perfectly neat and tidy, just like those children in the clothes catalogues. 
A fun story to try to impress upon young children the importance of getting dressed quickly and properly. 