A kundalini “rise”, I assume, is a minor happening when the energy of the body moves up the spine. It can be experienced through many different ways.
I’m not sure why an “awakening” would be dangerous, because, as far as I understand, it is simply the stirring of the energies, before they begin their rise. Unless what they are referring to is the completion of the kundalini.
The “serpent kundalini” lies dormant within the body, and once awakened, begins its rise up the spine.
I am working with the instructions given by Dr. Glenn Morris in his book Path Notes of An American Ninja Master.