So, since the harpies are a mixture of human and avian features, does this technically count as a furry story?
Joking aside, it's cool to see what is essentially Greek mythology fanfiction, in this case the story of Jason and the Argonauts (the original myth, though, not the film). I'm not sure if you actually looked this up or if the idea of sexy harpies was just the basis for the summary, but the first mention of Ocypete and Aello, in Hesiod's Theogony circa 700 BC, actually does seem to indicate that they are beautiful, and it's not until Aeschylus starts writing the better part of two centuries later that they get described as hideous.
The story also raises a rather interesting question: are sentient instruments of divine punishment necessarily on board with what they're doing? Traditionally, one might assume Ocypete and Aello were just monsters Zeus sicced on Phineus, but I like the idea that they didn't necessarily enjoy what they were doing. The Greek Gods have kind of a record of being dicks, after all, so it's hard to say it's out of character for Zeus.
Considering the limited word count allowed, the sex is still pretty erotic, and the sisters' avian characteristics (trilling, for instance) aren't so pronounced as to be offputting.
Finally, the Bio major in me wanted to rebel against the idea that human had impregnated harpies...but then I remembered that this is Greek mythology, where the Minotaur was produced when Pasiphae had sex with a bull. Granted, it was a magic bull, bit still, this is just how things go in these myths.
Dropping a note to say I read this one! It says written for a prompt, and it seems less inspired than usual for you - very little depth into the motivations, short, somewhat lacking in details - but I enjoyed it anyway. Greek mythology lends well to any coupling becoming plausible, what with every Greek figure getting it on with pretty much anyone. I was curious how you'd handle the setting.
favorite lines:
"a simple cloth covered his empty sockets" - that seals the image pretty well.
"batting playfully at each other’s talon tipped fingers to snatch him from one to the other while their songs rose in pitch and intensity." - talon tipped fingers (maybe a hyphen should be there) and snatch behaves like onomatopoeia with the "tch" sounds.
You know, I actually forgot I was reading a prompt response. You used the words so effortlessly, and that's a hallmark of your skill as a writer. Gorgeous, start to finish.
On a personal notes, I could never use Aello in a story such as this, because, well... "Aello" makes me think of Danny Aiello, and the image of a creature that is half bird/half Danny Aiello is too horrible to contemplate!