There are significant differences between corporal punishment and the infliction of pain for the giving of pleasure: technique, reason, and effect come to mind right away.
A person can endure a significant amount of pain from a whip, strap, hand, or paddle if their application begins slowly and builds to a higher, faster, and stronger level. This technique is used when the spanking or whipping is meant to give pleasure to either partner. "Warming an ass" prepares it for heavier discipline as the body adjusts itself to increasingly higher levels of pain. When the discipline begins at a higher level of intensity, the pain is much more difficult to tolerate.
During the times that pleasure is the reason for the spanking, there is (usually) a warmth, camaraderie, and intimacy that is lacking when the punishment is for the sake of punishment. At such times, caressing, kissing, foundling, and stroking are often intermixed with the application of pain.
And lastly, discipline feels different and effects a slave or bottom differently. Whereas many bottoms enjoy a paddling, most will do their best to avoid the paddle when it is applied as a punishment.. Strange as it may seem, the purpose and technique create a wholly other experience when the top wields a whip as a means of correction or penance.
Many novices (and some not so new to the scene) think that both forms of discipline are the same --- but they aren't. Discipline is a significant tool in a master's repertoire, but it is one that is often misunderstood and misapplied.
Real discipline "works" best in relationships that have continuity to them. It is meant to alter behavior. That doesn't mean that paddling and such can't be part of a short term scene. It certainly can be, though intense discipline demands a level of trust not easily reached in a fleeting encounter. Rule making, breaking, and the subsequent "punishment" are often part of the role-playing that occurs in SM encounters. I'm not going to presume to tell two (or more) people what should happen in their SM scene, but such discipline has a different "flavor" to it.
Some tops impose rules during a scene in order to create a reason for
punishment. Likewise, some bottoms break the rules in order to "force"
the top to punish them. In either case, if the scene works, then it is
right for its participants. But all too often such artificiality is uncalled
for. The simple recognition of rights and reasons can eliminate the need
for such "play-acting" entirely.
But the vast majority of Leather scenes never approach the intensity of a true master/slave relationship. Most of the time, the Leather scene is simply an acting out of fantasy. The "scene" is kept in the realm of play, and is seldom, if ever, allowed to effect one's life and lifestyle. That's the way life is, and it's liable to stay that way for a long time to come.
The problem with imposing rules in order that they be broken, or breaking rules simply for eliciting discipline is that both cases set up a scenario for failure.
At a recent "novice night" I was asked about a top who piled rules upon rules in order to make his bottom break them. It seemed he wanted force the bottom to deserve a punishment. The bottom, for his part, found it frustrating, since his intention was to please his "master", an unlikely job since the rules were impossible to keep.
The bottom would have been very happy to please his master by receiving the discipline. There was no need to force it on him. He was willing to endure it for his master's pleasure. Instead he felt a strong sense of failure since he couldn't keep all the rules his master had imposed.
As Larry, an experienced master says, "You don't need to break a rule for me to punish you. I'll do it just because I want to do it. If you want a paddling, don't fuck up, just ask me for it and you'll get it." Larry can speak that way because of his own self-confidence. He recognizes the rights and responsibilities inherent in an SM relationship and is comfortable with the gratifications they offer.
The best SM scenes are learning experiences. Discipline is a useful and necessary tool. With it a master can teach his slave how to behave and can help him modify his behavior to give greater pleasure to his master. Early on in their relationship, Jim, Larry's slave, often came prematurely, much to his master's displeasure. The application of a heavy black belt across Jim's ass cured that habit very quickly.
There is more to the Leather scene than play-acting. It can be more than
pleasurable. Like all relationships, SM can provide an environment for
personal growth and deep meaningful relationships. When two people come
together with mutual respect and understanding, they open themselves to
a world of miracles and delight. No matter what connotation you give to
the word "rod", use it wisely and it will reward you immensely.