I've read that it's possible to shut off your feelings and everything, not being responsive to the outside world at all... sort of there being no one "home" in the body, if you know what I mean?

I sort of get like this sometimes, when triggering things happens. Then I "shut down" slightly, become a bit blank (not showing any feelings) and disconnected, feeling pretty numb. I know you can become even more disconnected though, to the point where you're not "home" at all. How does that work?

All answers, thoughts and so on are greatly appreciated as I'd like to know how to do this as fast as possible.