The vagus nerve sits inside the collarbone right next to the carotid artery. As a doctor told me once, if you're able to physically stimulate your vagus nerve, you need to get to A&E posthaste, lol
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8120162/
I think it's called the Susan Shore device, and nowadays is the main hope for curing tinnitus to some degree.