B is for Bondage

Bondage isn't really embedded into the spanko psyche, but (pardon the pun) is often its bed-mate.

The dynamics are very complex:  the relationship is consensual but when one partner is tied to a spanking frame, handcuffed to the bed or immobilized by the other partner's personal most enjoyable form of restraint, then both players - to some degree - are pretending that the session has become non-consensual.  Even though it really hasn't - not at its heart - both pretend the victim is totally at the whim of the spanker.  Why.    Because it makes the game far more intense.

There is not one chance in hell that a member of the vanilla community can understand why that works.

So - may I offer a bit of advice?   In your tale, by all means have someone incredibly securely bound to be unable resist the upcoming whipping - and since it is just fantasy, you might make her/him really not enjoy the experience - but (particularly if your characters are in a consensual relationship) do not try to explain the "why" of what is going on.    Your spanko audience already knows, and your vanilla audience (if they have stayed with your this far into your tale) will never believe you, even if they care to try to understand.

This will save you from taking on an exceedingly difficult writing chore, and improve the readability of your story at the same time.   Which cannot be a bad thing.

Now - should you really, really like to propound on why bondage pushes the intensity up a notch get your characters to talk to each other (using realistic dialog) about what is going on.    Use their curiosity about each other to unravel the mystery.    That way what might be read as personal posturings is turned into part and parcel of the plot, without ever getting you to look as if you are standing on a lecture podium.