At The Opera
As you can see, the comic is how I see Barnaby's relationship with Kotetsu: a "one-sided non-romantic love."
The prompt on the anon meme was Kotetsu taking Barnaby on a "date" to the opera, preferably Madame Butterfly. I'm unfortunately not classy enough to follow opera (don't even ask me to recognize any opera songs, go ask Barnaby for that ;>), but I saw parallels between the opera and T&B. If you don't know the story of the opera, I strongly STRONGLY encourage you to go to wikipedia and read the synopsis. It's long, but worth it.
For research, I watched the Madame Butterfly movie. Then my parents started to ask me why all of a sudden I became interested in opera. Then my dad suggested that it's because it takes place in Japan, and I'm like, "...uh no."
I felt my last T&B doujin was severely lacking black and had too much gray, so I went all out with the black in this doujin XD.