ASMR
Anyone heard about ASMR? Stands for Autonomous Sensory Meridian Response. Fancy name for brain tingles. Like peeling the plastic coating off of electronics, a great massage, or just someone speaking to you in a soothing voice.
I don't know if it's an actual medical thing, or if it's just something the internet came up with. In any case, there are entire Youtube channels devoted to it. Relaxing as all hell, though.
I knew about the phenomenon for years, but never knew it had a name (or an internet following) until about an hour ago. It can be great to relax and enjoy, though.
Here's one of the better channels I've found for it, which admittedly is all of about 15 minutes of browsing various links: