Thank you for sharing this! My tinnitus was medicine induced and is not really somatic; only in front of a fan or shower, when I open my mouth, I hear "shhh," but other than that, no change.
I see yours was noise induced, can you modulate yours?
Nope, I cannot modulate my tinnitus with jaw/neck movements, but when I sneeze or yawn it seems to get a bit louder; that might be more of a perception induced by my fear of making it worse, though, rather than an actual somatic reaction, because I try my best not to stress my ears, and after I sneeze/yawn I become very aware of my tinnitus.
On top of it, I have pulsatile tinnitus, which sounds like the wings of a bird flapping and it is synchronized with my heartbeat. I am pretty sure that this one is not related to the other, because I had it before the onset of noise-induced tinnitus (heavy metal concert). Interestingly enough, though, about 1 month after the onset of the noise-induced tinnitus, the pulsatile one started to present itself more often - before, I only had it when lying down at night and after smoking, now it's always here during the first half of the day.
The pulsating one is somatic: the more I lean forward, the more the "flapping wings" frequency increases, to the point that, when I am facing the ground, it is a constant hissing that sounds more like wind.
Although the pulsatile tinnitus is somatic, it is most likely not treatable by the Susan Shore device because a) in the Q&A they explicitly say it is not made for this type of tinnitus, and b) apparently, it is not an auditory/neurologic condition like other types of tinnitus, but it is related to blood pressure / circulatory conditions that I might need to figure out at some point.
Also, to be honest, the pulsatile tinnitus doesn't annoy me that much, I have had it for years and it never let me down.. the real annoyance is the noise-induced, high pitched ringing, because it is harder to tolerate, and because it seems like it's reactive to sounds and music (even when it's not loud) which in my case took its toll on my career as music producer.
I am also not sure if what you describe, with the "SHH" when you open your mouth in front of fan/shower, is not somatic. Reading around the internet and some answers here, it seems like the definition of somatic is still pretty vague and 'open', and even when only subtle modulations (like yours) are possible, then the Tinnitus should still be considered somatic, so there is hope!