are Vibrations you experience Physical or Internal?

[Who Am I]

I was watching Robert Monroe's story of how it all happened with him, and he mentions at around 5 mins in that the vibrations were not physical, but internal. is that true? because i swear i feel like my body is vibrating when it happens. and i never had a friend or anyone to look at me or film me while im vibrating. it would be nice to get a infared cam and record self at night to see if my body is shaking:P

[Szaxx]

They are some manifestation of the between states of conciousness. Ive had then strong three times in 50 years. They are a part of the process and do feel physical in nature. There's posts on here saying nothing external was noticed and one where the vibrations were shared.
I'm sure this will be expanded on. The strange feeling of them is easily removed with a thought of becoming physically aware.
This indicates it's more likely a product of shifting the concious you away from the body, some ideas have been presented over time, what it is is that we feel still is an enigma.