Based on my own experience and my interaction with others over the past eleven years, I think I can safely say that most couples initially have very genuine practical reasons for introducing DD to their relationships. These are mainly to do with the desire to have an effective tool to help them reduce and deal with areas of conflict and disrespect, provide structure and security and encourage a healthier and safer existence.
However, when you look at things a bit more carefully, I think, for many people, there is a great deal more to it. To begin with, religious reasons apart, why would two legally and socially equal competent adults in a life relationship choose a dynamic that effectively gives one power over the other and why would a woman (or person with submissive tendencies), when considering the qualities they would like in a partner, be more attracted to a person with an air of caring authority and decisiveness, than one who is pleasant and easy going, but doesn't have those qualities?
To take that a step further, assuming that many start off with little or no experience of the effectiveness of spanking as a correctional tool and that others only have negative childhood memories of how it was used, why is it that many of our very different (from childhood) adult selves are attracted to the specific concept of spanking as a tool of correction?
There are of course exceptions, but personally, I believe that it is to do with the fact that each of us is 'wired' in such a way that we find a more dominant or submissive (respectively) personality attractive in a partner. (And what more tangible demonstration/experience of dominance/submission than the act of one person being put in a position where they can consensually physically discipline another who voluntarily submits to this?). Since we are adults, with adult attributes and feelings, this extends into all areas of our relationships, including sexuality. I'm not saying that this is the whole deal with the relationship, but only that it is probably an important contributor to the choices we make, even if we are not conscious of it, or choose not to acknowledge it as such.
If that seems like a step too far, how about talking it down to a more grass roots DD level?
Since it is a relevant factor here, I will start by saying, that when I refer to "erotic" or "sexual" in the context of 'real' punishment, I am speaking only of the natural feelings that can occur as a result of the (disciplinary) D/s interaction between two adults in an intimate relationship and not of any purposeful attempt to 'mix' sexual spanking with discipline in the same session. I say this because, in the eleven years during which I have interacted with other 'serious' DD couples on the internet and in real life, I have only twice, both times very recently, heard people voice the opinion that this actually occurs in genuine DD relationships. In one instance it was suggested that some people 'eroticise' punishment by incorporating sexual touching, rubbing and verbal sexual suggestion. In the other, it was said that some couples, on identifying an infraction, decide to 'deal with it' by sharing a sexual spanking and calling that "punishment". I can only say, that in all the years I have moved in DD circles, I have never once known anyone to describe "punishment" or its erotic element in either of those terms.
In my experience, what they consistently mean when they speak of the 'erotic' element in punishment is what I have described below.
Ask almost any individual who considers themselves to be "strictly DD" and not 'into' what they think of as the more 'kinky' and 'artificial' world of D/s (or, if they happen to indulge, consider that aspect of their relationships to be entirely an separate animal) and you can be pretty well certain that they will tell you that the 'evidence' of this in mainly in the fact that their disciplinary spankings are "real" because they are "aren't sexual in any way" and the experience is an unpleasant one. Then ask them how they feel after the discipline is over and the great majority will reply that they feel much closer to their partners in every way, including that they find them more sexually attractive. Some will also sometimes feel quite comfortable about sealing closure on the infraction and punishment by reconnecting sexually as a first step to moving on once the discipline is over and done with. Most will say (although they might use different terms to describe it) that part of this reaction comes from appreciation of how "right" the dominant/submissive interaction feels.
Ask any person who embraces the D/s aspect of their relationship and might enjoy erotic spanking as a bedroom activity how discipline works for them and they will say, (guess what?) that they very much dislike the experience of being spanked for discipline because it's a serious and 'real' business with a completely different atmosphere, significance and feel from a 'play' type spanking. Then ask them how they feel after the discipline is over and the great majority will reply that they feel much closer to their partners in every way, including that they find them more sexually attractive. Some will also sometimes feel quite comfortable about sometimes sealing closure on the 'over and done with' infraction and punishment by reconnecting sexually as a first step to moving on once the discipline is over and done with. Most will say that part of this reaction comes from appreciation of how "right" the dominant/submissive interaction feels.
If you are thinking that I've repeated more or less the same thing for both categories of people, then you aren't wrong, because I have found over the years that what the two sets of people say about their supposed "differences" only goes to show that in the great majority of cases, there doesn't really seem to be much of a difference at all. Of course, as in anything else, there are exceptions to this "rule", but they honestly don't seem to be very common.
So what I think it's worth asking yourself if you feel that your disciplinary spankings aren't 'working' is whether your problem is really related to what you do after the punishment part is over and done with and you are supposed to have used your "final closure" tool of a disciplinary spanking to deal with and get past any division that the infraction caused, or does it have to do with the fact that you perhaps aren't setting the tone and atmosphere of the actual discipline to be different from that of a sexual spanking? That is not to say by ritualising and creating a stylised setting which is quite likely to end up escalating the feeling of artificiality by giving it feel of a 'role play', but following where the natural and unforced presence of an entirely different emotional and psychological atmosphere leads you. As adults, I would suggest that few of us are unable to recognise genuine displeasure in a person with whom we are in an intimate relationship and that it's more than unlikely that we will confuse this with pleasure and won't be aware that we are being punished.
Assuming that it has to do with the second factor, can what you do *after* the punishment is supposedly finished make any difference to what happens *during* it? Is it going to make the spanking that you've just experienced less physically painful and emotionally memorable, or alleviate any of the lingering after affects?
Also, is there anything constructive or useful to be gained by denying yourself whatever kind of reconnection, be it sex, or whatever, seems natural and desirable to you as a couple, once the punishment has been concluded. Similarly, are you 100% certain that by making a special point of controlling whatever you do afterwards by directly linking the 'reconnection' to the discipline, you won't be carrying on the punishment indefinitely thereby losing the effectiveness of DD as a tool to deal with and conclude an issue once and for all?
I know that there are people who believe that, if you sometimes (and I stress the "sometimes", because there are no "rules" about this and it's usually just a case of whatever transpires naturally between the couple at any one time) happen to progress into making love after a disciplinary spanking, it can create some kind of undesirable connection between punishment and pleasure, but realistically, since, whatever their 'official' feelings on this and whatever they actually do after punishment, most people seem to experience much the same emotions and effects both during and after the spanking, is this statistically likely? The only difference seems to be that some people act on whatever seems right in the moment , which doesn't have to be sex and can be a case of just carrying on with your lives, and some people feel bound by some kind of protocol they for some reason think they "have to" follow in order to make it seem 'correct'.
I also fully understand that there appear to be instances in which punishment isn't effective because the same offences continue to be repeated and that some people have the believe that this is because of a punishment/pleasure association which encourages those repeats. I would suggest that, while this is possibly true os some couples, it is just as likely to be because old habits take a while to break, things get forgotten, or just because there is often a lack of consistent and/or effective disciplinary response when a couple is new to DD and are finding their way.
So what I am saying, is why not forget the labels, the "must dos" and the fact that someone else might see your genuine discipline as kink or eroticism and just go with whatever works best for you as a couple and maintains the happiest level of relationship?