Allow me to expand, just in case someone doesn't want to look this up. Until about a week ago, I thought, relying on just surveying a few close acquaintances, it was a pleasurable phenomenon isolated only to me. Then, on another forum, I found out that that is not the case; thought it only recently has received any attention from the research community. Here's the deal in a nutshell: while, in a relaxed state, listening to music, or a person's voice, or giving one's attention to just about anything else, one experiences (for most) a pleasurable tingling sensation about the shoulders, along the back of the neck, as well as the back of the head. It's not intense; though, I, for one, will do whatever I can, within reason, not to disturb the sensation. For me, it doesn't "arrive" that often.