Surrounding the second and the third chakra is the Void which stands for the principle of mastery (guru principle) within us. In many spiritual traditions, this area is the "ocean of illusions" that needs to be crossed with the help of a spiritual guide. When the Kundalini is awakened and passes through the Void, this principle of mastery is established within us. Thus, as Shri Mataji says, in Sahaja Yoga you become your own guru, your own spiritual guide since you can feel on your fingertips all your subtle problems and have the power to cure them using your own Kundalini. Moreover, establishing this center helps us get rid of all our habits, laziness, gross attachments, and everything that enslaves us in a way or another: we become our own master.
Following false "gurus" who are more interested in power tricks or your purse can damage very much the Void area. But after Self Realization, everything can be cured through the purifying power of the Kundalini in meditation.