How I learnt to switch off my thoughts like a muscle

Hi Reddit, just to preface this I wanna say I'm 19, not a monk or a neuroscientist but I've figured out a way to stop thoughts instantly almost like flexing a muscle.

Step 1: When I first started, I'd close my eyes and only focused on the black in my vision, when my mind wanders off bring it back and focus on the black again.

Step 2: Over time this became automatic. Now I can just "tense" the front of my brain and the thoughts switch off. I do this every night to help me sleep since I've had trouble with insomnia

Extra observations
Regular thoughts are a lot easier to turn off than music stuck in your head, with music it feels like I have to "tense" my whole brain rather than just my front.

Not saying I'm enlightened or anything, just sharing whats worked for me. I'm curious if anyone else has experienced something similar.