HOW TO STAY AWAKE?
Try practising at a point in the day when you feel energised, rather than depleted. This could be first thing in the morning, and it might also help to engage in some activity beforehand – perhaps you already have an energising asana (postures) or pranayama (breathing) practice.
We typically practise Yoga Nidra lying down, therefore one trick to stay awake is to keep a forearm off the floor so that as your body falls asleep, your arm sinking to the floor alerts you to this.
You could also consider sitting up, or even standing up for the practice. Not only will this help keep you more alert but it will resolve the tendency to make experiences state specific, such as that you can relax and find peace lying on the floor but in waking life you lose that sense of calm.