After my epic failure with Katie's animation, I went back to re-evaluate my workflow. It's not as if this is the first time someone tries to make animations with multi-hour rendering times.
The solution is to use pre-vis and layout cuts to reduce time and manage complexity (here's Pixar's Brave, showing a rather more ambitious scene).
The basic animation for Chloe is a 30 frame sequence (1 second long). It's hand-posed (meaning I set up the keyframes manually, rather than using mocap data), and initially rendered using Basic OpenGL, taking it into After Effects and testing how it loops. I did a couple of really quick tests like that; if I'd had the sense to test out Katie's scenes in a similar way, I could have taken a 15 hour animation and tested it in a couple of minutes. Live and learn.
The second thing I'm playing with is better use of re-timing the animation. Previously I used DAIN to stretch an animation, but in this case the 1+1 second timing is actually fine for a basic blowjob. Instead I bumped the animation rate to 60 FPS, so that when I tweaked the timing you don't feel any frames that's being held for too long.
Now, all of this is overkill for a quick looping animation. It's neat, and I enjoy improving as an artist, but it really doesn't matter much for something that short.
Like most things in life, it's a bit of push and a bit of pull. Katie's snafu provides the push; one of the central story-sequences in Act V provides the pull. I include the basic layout cut (there's not really any spoilers in there). The placeholder music is Warriors, by 2WEI and Edda Hayes (used in League of Legends).