It's all the little details.
Like, okay, so I write this scene and it's kind of a gross scene, on purpose because what's happening is awful and I'm trying to be realistic, right? And basically the character is cleaning up vomit, trying to hide it but he has nothing to clean it with and nowhere to hide it. So he cleans it up with his hands and it all very graphic and that's awesome because that's what I was going for.
My beta told me it was excellently gross. :D
And then she's like...'but if you want to tone down the grossness a bit, maybe have him use the corner of the sheet? Because you didn't even have him clean his hands off when he was done.'
*Dammit*. OF COURSE he cleaned off his hands afterward, the whole point is to *hide* the evidence and I know that he cleaned off his hands but if I don't type it onto the page then no one else knows because as wonderful as my readers are, they're not freaking psychics!
Or at least I hope they're not because man, there is some weird crap in my head and no one needs that.
Why can't all my writing just be, 'And then they sexed. The end.'
But noooooo...I have to have delusions of plot.
ps: and even if it was just 'and then the sex' fic, there's still all the limbs to keep track of and the anatomical rules of reality. Like I one time commentboxed a fic for a kinkmeme and when I went back to edit it later I realized that the guy would have had to have been an acrobat of *incredible* flexibleness in order to do what I said he did.