Quote by sprite
so, authors... think about ALL the stories you've ever read. Hemingway? Patterson? King? Tollkien? The Bible? how many of them had dialogue that looked like this:
"MAKE ME CUM!" she shouted.
the answer? none of them. there's no real good reason to capitalize every letter when writing a story. just the little descriptor - she shouted - should give readers the idea. just because you've seen it on other porn stories, doesn't mean it's the way to do it. also, adding letters - i'm going to cuuuuuummmmm! - is just as bad. stop it. please.
I like all caps, and repeated letters. Sometimes they are the perfect way to express anything loud or out-of-control - e.g. anger, orgasm etc. J.K. Rowling uses all caps, as does Terry Pratchett, and George Orwell. Jaymal, CarltonStJames, VioletVixen, and doubtless many others use them, along with repeated letters. DeviantSusie makes a positive art-form out of repeated letters, and she does it so well: have a look through her stories, and you'll see what I mean.
Why not just use descriptors? Well, you can - and sometimes this works very well. But I like, when possible, to show rather than tell. Expressing the "music" of a character's speech, i.e. its rhythm, its resonance, its weight, its pacing, through unconventional orthographies, can save unwieldy descriptive vocabulary, especially at a moment of high drama in a story, or a sexual climax. It conveys the subtleties of how that character is feeling, without too much narrative intrusion. "I'm c-c-cccoming" is completely different from "I'm cominnnnnng..." from "'M COMIIIIING!!!" Read them out loud, and they make you feel different - in a way that narrative description can struggle to achieve.
Yes, it's pornographic. But we are writing porn, aren't we? Porn is "the depiction of erotic behavior (as in pictures or writing) intended to cause sexual excitement". Whether we describe our stories as porn, or erotica, or smut, and whatever our personal stylistic preferences, it's all about fucking. There are different literary styles available to us pornographers, some more appropriate to certain contexts than others. But these different styles lie on the same spectrum. They can work in partnership, rather than opposition.