The last time I meditated I found something that works for me,so I wanted to share it with others here.I have been reading many posts,where members are saying that they are feeling great heat in their spines.Well I am finally feeling that heat myself.While am doing the twin sepent,I visualize my Shashumna a bright red color,and then when my serpent goes through each chakra,I see my sepent as red fire too.When I did it this way,I did feel that heat that everyone has been talking about.Hope this may help someone else too.