Upright Shavasana refers to the position of your neck and spine when you are lying down on the ground in a corpse-like pose. So, while you lay back, make sure your core is engaged, and your lower back is connecting with the ground. First, move your neck slowly from side to side and then gradually settle down by stabilizing your neck upright in the center of your yoga mat. Again, make sure that your neck is sinking into the yoga mat and there are no gaps between the two.