There are three types of skits. Long skits are divided into three types: Main (which concern the events of the Main Chapter), Character (which are related to the Character Episodes), and Etc. (which cover miscellaneous topics).
You can watch previously viewed skits in your Skits list, but you only get affinity the first time they are viewed. To watch the long skits, you must press the Select Button to trigger them when the prompt appears. Short skits occur automatically when certain conditions are met.
Battle skits occur automatically in combat when certain conditions are met. Some skits are time-limited and covered in the Walkthrough so make sure you don’t miss them. Check the Data section for a list of skits and trigger events.