Kundalini is a powerful concentrated life force energy that, according to the Yogis of the Hindu tradition, is coiled up like a snake at the base of the spine in your first chakra.
When Kundalini is awakened through the practice of yoga, it rises. This is called the Kundalini Rising. See the illustrations below:


Kundalini take a spiraling path as it moves up from the base of the spine to the top of the head and out. When the Kundalini Rising occurs, the release of the energy raises your own vibration so that you are now operating from a higher spiritual place.