As for the vibration it's uuuuuuu-rrrrr-uuuu-zzzz (that's to answer your first question)
As for your 2nd question that probably because just like our physical bodies we have to know our limits before we over do it,so the same for our chakras....but then that's just my observation if any other brother or sister who have been a dedicated Zevism longer than I,then please feel free to help and or correct if I am wrong
