Don't know about the tuning fork one, but there is a method where by if you poke some muscle on the back of your neck repeatedly, it stops for some people. This is apparently due to that muscle being the thing that makes a noise, and poking it eventually physically exhausts it temporarily. Obviously that only works if that's your cause.
Masseter and suboccipital muscle massage that I read about on Reddit of all places instantly reduced my subjective tinnitus by maybe 90% about five years ago. It's not permanent but lasts months and has worked for me for years. I now need near total silence to hear the tone, and it completely resolved the condition as a daily problem for me.