A dean is the head of a section of a school, this might be a class year group (e.g. 5th Form Dean), or a department (e.g. Dean of English) and are responsible for the overall well being of their section.
Deans and spanking
As a dean is in charge of looking after a year level in a school, they are the ones who have to deal with disciplinary problems that transcend more than one classroom, or in schools that limit a class teacher's disciplinary powers, all disciplinary needs of the students in their year. This frees the teacher from having to stop the class to deal with a disruptive pupil. Deans often have the perspective to see if the problem lies in a particular teacher/pupil relationship by how a student relates to his other teachers, without being colored by how the student behaves in their class.
In schools that use corporal punishment, the dean may mete out such punishment in his/her office, using the implement associated with their year group (e.g. slipper, strap, paddle, tawse, cane, or birch).
The Tale of the Dean's Wife (1970) is a grind-house sexploitation film (i.e., a "nudie-cutie" sex comedy). In this story, the titular wife of a college dean is given a severe belt spanking as part of an experiment in "pleasure through pain". She turns out to be a masochist who is stimulated by the punishment.
A number of underground spanking videos are based on stories where a male of female dean punishes a student for some transgression. For example, in Schoolgirl Blazer and Seared Rears (from Dallas Spanks Hard), Dallas plays the role of Dean of Discipline who thoroughly punishes students at a girls' school.