Make her soil her diaper, hopefully it is soft and squishy. Remove the diaper and then hang it around her neck to use as a bib. She will have to constantly smell her excrement. Do not put another diaper on but rather have her tell you when she has to pee/poop again and then put the bib diaper on for her to use. If she has an accident, then she will have to be punished further but this is a good way to teach the little ones a lesson.