DrAnthill
This is an older KNT one-shot I wrote and shared on reddit, and I figured you could enjoy it as well. Note that when I wrote this, I had even less knowledge of how the Ayumu scene went than when I wrote Dr. Akira's Sanatorium, so consider this an AU.
Anyway, if you think that Akira's psychological torture and brainwashing is going a bit easy on Bert or you just want quick and simple, but still painful and humiliating karma, this is a story for you.
And of course, as before:
Look, either you are familiar with KNT, or you're lucky. I won't waste time introducing you to the original plot. If you don't already know it, do yourself a favour and don't look.
I have, personally, not read KNT and I intend to keep it that way. Everything I've learned about this vile tome of depravity is from discussions in anti-ntr circles and several chatbots based on various points of the story.