Genre gets described either as a straitjacket or as a cynical marketing category, and it is neither. A genre is a set of promises that readers arrive already holding, and the work either keeps them or does not. That is a useful frame, because it turns a vague argument about creative freedom into a specific question about which promises are being kept.
The practical value is that promises can be listed. Once you can name what readers expect from a given kind of work, you can decide deliberately which to satisfy and which to break, rather than doing both by accident.
What a genre actually promises
Usually a subject, a tone, a rough shape of resolution, and a level of explicitness. Sometimes a pace and a setting. Readers choose work by these promises, and a work that breaks them without warning disappoints readers who would have enjoyed a different work by the same person.
Not all promises are equal. Some are load-bearing, meaning the work stops belonging to its genre if they are removed, and others are conventions that could be dropped without anybody minding. Telling those apart before breaking anything is the whole skill.
Meeting expectations earns trust
Readers extend patience to work that has kept its promises so far. A book that delivers what it advertised for two chapters can do something surprising in the third and be followed rather than abandoned, because the reader now trusts that the surprise is intentional.
This is why consistency matters commercially, as set out in the piece on explicitness as a choice. An audience that knows what it is getting is an audience that subscribes; one that has been surprised unpleasantly is an audience that stops opening the notifications.
Meeting only expectations produces nothing
Work that delivers exactly the expected in exactly the expected way is comfortable and instantly forgettable. Readers consume it and remember nothing, which is a poor outcome for anybody hoping to build a following rather than fill a slot.
The difference between competent and memorable is almost always something specific: an unusual setting, a relationship that behaves unexpectedly, a formal choice nobody else is making. One departure is enough, and one is easier to execute well than several.
Break at the level of execution
The reliable approach is to keep the premise-level promises and take liberties with execution. Deliver the subject, tone and resolution the reader came for, and make the specifics strange. That satisfies the promise while producing something that has not been read before.
Breaking premise-level promises is possible and much riskier, since the audience that arrives is the wrong one and the audience that would have wanted it never hears about the work. Where it is done successfully, the work is usually marketed as something else entirely.
Conventions are not all arbitrary
Some genre conventions exist because they solve a problem. Recurring settings frequently exist because they allow a particular kind of privacy or proximity between characters; structural habits often exist because they pace a story well. Removing one without knowing what it did tends to create a hole.
The historical version of this argument is in the piece on where the genre words came from, where present-day conventions turn out to descend from decisions made for reasons nobody remembers.
Signalling honestly
Whatever mix of keeping and breaking a work does, the cover, title and description should signal it accurately. Readers judge a work against what it advertised, which is the mode-signalling argument in the piece on erotic and pornographic modes.
Accurate signalling costs nothing and prevents the specific failure of work that is genuinely good being received badly because it reached readers who wanted something else entirely.
Using a genre rather than obeying it
List the promises, decide which are load-bearing, keep those, take liberties with execution, and signal honestly. That is how work stays findable and stays worth remembering, which are the two things a genre respectively helps and hinders.
Characters here are fictional and unmistakably adult, as set out in the reader agreement.