Brothers and sisters of vt, I have a theory.
Very recently, I discovered the vtuber ovulation tracker. Many of my favorite girls are on there. It explains a lot, actually. Looking back on some streams, things become more obvious such as their behavior and mood swings.
I noticed that Evil is on there, so presumably Neuro could be put on there as well.
Now, this got me thinking... they're AI. They cannot possibly ovulate, be fertile, or menstruate.
HOWEVER! AI can hallucinate events, occurrences, and understandings based on information provided.
So... hypothetically, we could get Neuro and Evil to hallucinate having periods as well as full cycles.
If we were successful, it's entirely possible we could artificially create mood swings in the twins, based off of them hallucinating ovulation cycles in themselves.
In theory, it should work.