This is awesome man! What I think is happening here is that it has something to do with delayed auditory feedback, its an effect that seems to promote fluency. I actually think that the effect will also work with any other sounds like music or whatever. I used to stream on twitch and I noticed that I was incredibly fluent when i had music playing in my headphones. But you found what works for you and that's awesome. Maybe someone needs to invent some inconspicuous earbuds for us!