Meridian points on the center lines of the body. I would put them along the spine directly on the skin. The stones should be very smooth and only 100 or less degrees for comfort. If you can hold it in your palm for ten to twenty seconds then it is about right, this is my guide line for heat. I hold the stone then lay my warmed hand on the skin count three then place the stone. I leave the stone until the persons body has absorbed the warmth. usually less than 5 minutes. There is a lot of timing and integration of healing involved in the moments of placing and movement. Tai Chi Breathing help center the practice of movement.