Burgundy:
The second kind is the story where all the characters appear to live in an alternate reality, in which everyone involved unquestioningly accepts any discipline they are subjected to. The rules seem to be that any adult with any type of authority can decide to spank anyone they want, and no subordinate adult is allowed to say 'no'. (Thirty-year-old man visiting home: "Mom's house Mom's rules, so I guess I'm getting a spanking for downloading porn." Twenty-five-year-old woman at work: "I spilled hot coffee on my work laptop, so of course my boss will spank me for it." Eh? No?? Why???) Every other interaction and all other elements of the story world are ordinary business as usual, except for that.
But this second type of story doesn't get comments complaining about implausibility. Am I just being difficult, to be shouting "why?" in my head, to need a reason for why adults would put up with it? Is it just an accepted genre, and I should just chill (very likely) and take it at face value? I've read some excellent stories of this second type, but the 'why?' refrain in my head kept needling me throughout.
So here is my question, finally: authors who write the second type of story, what is your head canon about the world your characters live in? In a story where every other aspect of daily life is just normal, why are spankings not a kink but a fact of life, and what's your reason for adults accepting them?
Well, speaking only for myself, I'm thinking of a motion picture saying by the Chinese detective Charlie Chan: "Unlikely events allow themselves the luxury of occurring."
That applies to "unlikely adult relationships" also, I'd venture. Charlie doesn't investigate the vast majority of situations in life which don't involve serious criminal activity, his stories/movies deal with the ones which do. In my "Sisterhood"-related accounts, the very small percentage of FLDD (female-led domestic discipline) marriages/relationships in a particular area are the ones I'm writing about.
In a story within which a consensual adult spanking arrangement exists, the reasons for it may or may not be explained, because in fiction plenty of situations exist which aren't explicitly explained by the author--they're described to the degree that the plotline is enhanced by such a description, yet it may be up to the reader to speculate as to why they came about in the first place, if it matters that much to him/her. (Some spanking-oriented stories will indeed provide such insight into the relationship's origin, and/or it may be provided in other related accounts if there are recurring characters involved.)
If an "overall consent" has been granted, in any particular situation the spankee may not believe that he/she deserves to be disciplined, yet he/she still cooperates because the spanker is considered to have the superior judgment concerning what is best within their arrangement, of whatever kind it is. (Look at the last line of KD Pierre's story, "The Friend," which summarizes this concept.)
So if the adult characters involved are accepting, for whatever reason(s), that one or more of them should have disciplinary authority over one or more of the others, as a reader at that point I'll generally accept it and keep reading, although I may comment on it either favorably or unfavorably afterward.
Consistency strikes me as important though, so if a thirty-year-old woman willingly goes panties-down over her mother's knee during a visit back home, based on the "Mom's house, Mom's rules" concept, on one occasion, unless there's any described reason for a reversal in attitude, I expect her to be equally (albeit perhaps grudgingly) cooperative in undergoing a maternal spanking the next time she violates those rules at her mother's place.
The type of story that doesn't involve an established disciplinary arrangement, therefore involving some singular reason for one adult to accept being spanked by another one, I enjoy reading that kind of account on occasion--even if the circumstances may seem contrived and/or difficult to believe, they tend to be intriguing to consider.
"Unlikely bottom-blisterings are still fun to read about..."

--C.K.