Just in case this helps anyone:
If I lie down in bed with earplugs (I sleep with them, so this is every day) and concentrate on my tinnitus tones in a certain way, I can make them go away for a bit. The "technique" if you want to call it that, is to imagine I've applied a notch filter to the tones, and I'm gradually lowering the gain.
It probably sounds silly and on-the-nose for an audio forum... but I think this works for me because I've used PEQ so damn much in my life. I started playing with FL Studio almost 20 years ago, and so this is a pretty well-ingrained idea for me. YMMV.
The core of it is for my conscious mind to remind ... whatever part of my brain is responsible for tinnitus that the tones aren't real, and that I would like them to go away.
They always come back after a while, but if I am feeling bothered by it, it gets me a break for an hour or so.