I image the entire soundscape (what I'm possible of hearing) as a long, thin line which is warbling a bit, as I'm hearing things right now -- like the line in an oscilloscope. The present tinnitus represents itself as a sharp spike in this visualization, the location dependent upon its texture (sharp pings, or a low muffled warble).
I then imagine a giant hand (my hand) on top of that spike, pushing it down, slowly, and as I push it down, the tinnitus subsides (since I know what that subsiding sensation feels like). Sometimes I have to do this pushing motion a few times before the spike slowly attenuates by itself and it joins the surrounding levels.
The entire process takes about 30 seconds, and doesn't work every time. If after a few attempts it fails, I abandon the visualization exercise (lest my brain somehow learns the pushing motion to be ineffective).
It's not entirely clear to me how / why this works: mapping a physical phenomenon onto an abstract mental visualization / picture, and then manipulating that mental picture and thus the physical phenomenon.
I'm also very musical, so these sorts of visualizations tend to come very naturally to me.