How in the fuck does it make any sense that there's still 2 animations left when the art is 100% done?
That's retarded.
To my knowledge the process is this:
-DC draws a still image of a h-scene and splits it into loads of tiny little layers.
-file is sent to AEHentai, with explanations of what sort of movement is desired in the final animation
-using the many layers of the .psd and DC's instructions, AEH uses After Effects to construct a rig for the animation
-use rig to construct "bone-animated" h-scene
-tweaks to make sure DC is happy
-render out into about a dozen keyframes for use in Ren'Py
The rigging step is what I imagine takes so long. This whole process is AEHentai's trademark (literally in his name), and it's well-known as a fairly slow process. Results are good tho