Smorg is giving St Peter the 7!
I turn my brain off by focusing on some thing that reminds me what need to do. For example, when i am down, preshot routine and stroking i count my practice swings. Nothing matters at that moment but those numbers. And when i hit 5 i stroke through.
I force myself to repeat an action by reinforcing it with words. I always did this. In baseball i would count to time my swing. Because i counted how long it took the ball to get to the plate. Basketball free throw i reminded myself with a mantra of "knees, fingertips, up". Each step of my throw.
Saying it out loud really helps me avoid distractions, forces me to follow through.
People might think you are goody for talking to yourself
You are tying up your brain to keep other thoughts out but that isn't the same as having the conscious mind at rest. The goal is to have no thoughts in words, even worse from the standpoint of shutting down conscious thought is speaking the words aloud.
Road hypnosis might be a cousin of where you are trying to get, I don't know. Some of the conditions reached through martial arts or meditation again might be close. Never been there through these means or worse than any other method, medication of any kind, or perhaps I did as a two or three year old, I had an odd dream under ether.
We don't really have the answers yet but what you are talking about is what J Michael Plaxco calls the level two zone in his book. Level three is where things really get good.