When Mark becomes a substitute teacher, he sure is in for a handful with his precious, innocent students. His first grade class includes playful little Michelle Tanner, Denise Frazier and Aaron Bailey. When Michelle and her friends demand a very vivid acting out during story time from Mark, which in the end borders on torment, he does a trick to get them to be quiet - and ends up hurting his behind. With his tailbone being broken, Mark is in great pain and confined to a tooshie-donut. Michelle feels very guilty and comes over to 'help him'. John Stamos also makes a guest appearance as Jesse Katsopolis.