Hey, been a long time !
I've listened to kei' demon girl files a lot, combining it with psychedelics and I had pretty insane results.
For instance in the files you often have the pattern "when you will do X, you will hear demon girl say good girl, and you will feel good", and I had this effect for several days when I was following the instructions.
Also literally had a mental block to do things "not permitted" by her. I am very genderfluid and after these sessions I had the impossibility and no will to boy mode, always had to go for the hard feminine side.
On long term basis, I am definitely way more feminine than masculine now.
I've listened to most files of the DG series so if you have questions do not hesitate !
The most insane experience was one day where I kinda abused on dosage and raw listened to the Demon Girl's Mind Trap Week 1 (4 hours file with super extensive details on body transformation and cie) and I had a complete submersion in the file, with hard visualizations of the demon and a feeling of being possessed. At one time I was totally convinced on the body transformation part it was a pretty crazy experience.