Just to be clear, we don't actually know what that does right? Like, there's no link to this making up for poor sleep or improving your cognitive function right?
Feels like a gentle rub on the skull from inside, and the overall feeling is akin to that of a lucid dream, but with a bit of nausea. Not too pronounced of course, but detectable.
https://www.paulkeeble.co.uk/posts/cff/