Its a common occurrence in people first Experiencing Kundalini to have intense energy in their feet and for one or both big toenails to turn black and fall off. Usually its the big toe on the left foot that is commonly experienced. This is a sign that Kundalini is active. Sometime after that the Kundalini will make its way up the Root Chakra (Located at Tail bone) and begin its journey up all the Chakras.
In my case, I did not experience this. I did not notice anything until It had begun to rise to my sacral chakra (Located lower abdomen). I find it strange that I didn’t notice any activity in my feet, legs or root chakra at all.