anon i don't even know if you're still here i need you to know that i switched computers back in october and forgot about this askbox. anyway if you are still here i am so sorry and also here is my answer:

the thing is it's very difficult for me to want to write scenarios that i don't really feel are realistic for the character. like for instance i really wanna write akishinji drunk sex at some point, but i've been hinging on the "well, why the hell would they be drunk. neither of them really seem like the type to", and i haven't really gotten around to working through this issue because i have like five other things i wanna get to first.

but i use this example to represent that if it's like a slight issue in the scenario, there's two ways you can really go about it. either 1) the fuck it we ball tactic where you just kind of brush over inconsistent logic and write with your dick. realistically if it's pornography, people aren't going to care That much. and if they do, they'll just click out of the fic.

the other option (and my preferred way of going about it) is providing circumstantial factors and overthinking the set-up. thing is people aren't monolithic. they act differently under different circumstances and mindsets. for example you can narrow in on a character's (or dynamic's) trait and exaggerate it, you can introduce new HCs (i love making shinjiro's libido go crazy after he stops using the suppressants, for instance), and/or you can make up issues that induce characters to behave slightly out of character.

for instance, i really like writing sexual frustration, since making characters pent-up generally makes them more eager. providing set-up that elaborates why a character might behave strangely for who they are renders the "inconsistency" way more feasible. realistically most people who read pornfic really aren't going to care about the minor details, but set-up still adds a lot to the overall to the vibes and present tensions.

i hope that helps. it's a little difficult to explain without providing specific examples, but my tl;dr is "don't sweat the small stuff Too much" and "set-up is great because it allows you to mess with the characters more".