I have two theories:
-
Someone is tuning in on you, trying to track your "thoughts".
-
You're tuning into a signal that's being broadcast that most people don't notice and helps brainwash them.
Basically, you might have turned resistant to frequency brainwashing and/or someone is concerned about what you're thinking about.
I hear it too, mostly around the time that my p. gland is being active, and I intuitively start thinking about unimportant shit to throw them off.
After about 2 minutes, the sound disappears.