I deal with CP (corporal punishment), spanking and caning as a separate topic from more general bdsm because it does seem to have it's own special place.

The schoolroom scenario features strongly, as does the image of the vulnerable person (the child within, connecting with the image of the school child) at the mercy of the teacher, the authority figure. Much of the love and nurture you experience in early childhood comes from authority figures who cared for you, hence the power and comfort of this image.

The other side of CP, spanking and caning, which may follow on from the childhood aspects is the use of it for personal atonement and punishment. If you are beset by guilt over you own actions (or inaction) one way of either dealing with the issue or opening it up is to take a punishment for it. A serious process, and often one involving a great deal of trepidation and fear, not to mention pain, it does work remarkably well. It tends to leave behind a life long addiction to CP play, but it gets much more fun once the real issues have been dealt with.

As a way of opening up on emotional issues, facing grief, coming to terms with life's challenges, CP has an important role to play. The accepting of pain, a 'payment' in kind in many ways, the nurturing you will receive through he process, the endorphin release and the sense of having done what you could, this all combines to make this a powerful technique.