I’m struggling to visualise this, do you have any references with images?

I never heard of the above, but I also have my own method that I discovered one night on some tinnitus forum:

1. Straight body, drop your head all the way down, chin to your chest. 2. Place the palm of your hands on your ears, blocking them, with the fingers to where the back of your neck touches your scalp. 3. Tap your fingers on your stretched, rigid neck muscles.

Just sharing it here since it has helped me and it doesn't help to have many techniques to battle this.

Put your hand like this: https://static1.bigstockphoto.com/9/5/2/large1500/259859530....

But with your thumbs closing your ear orifices.

Now you have to hit the back of the neck with the tip of your middle fingers, and to get a harder hit you "snap" the fingers, putting the finger like "fingers crossed" position, and the pressing the middle finger towards the head. You should hear a big "thump!" inside your head.

It aleviates the tinnitus for a few seconds, but more likely due to the stapedial reflex than anything related to neck muscles.

sounds similar to a masseter muscle massage https://www.youtube.com/watch?v=7VnV7wUxst0