People experience many different sensations while in yoga nidra. They can be tactile, audio or visual. Anything you experience is okay and perfectly normal, and to experience nothing at all is also okay.
The most common sensation is surfing — that feeling of coming in and out of awareness. Know that when this happens, you are still listening and hearing what is being said, you are just in a deep state. Even if you are snoring, you are likely not asleep, especially if you return back into the present when cued to do so. If you do fall asleep, then your body needs the rest and that’s is where you energy is being used. Know, however, in all the times I have guided yoga nidra, I don’t think I have ever had someone fall asleep.
Physical sensations also occur. Twitching is likely the most common. One explanation for this is that you are releasing the energy tied to a past experience or trauma that is being let go during you practice. Another is that, as you let go of the past experience or trauma, you are also letting go of the fight or flight response that is associated with it. Other physical sensations include losing the feel of your body, your body feeling extremely heavy or light, floating, bursts of energy, sounds and/or the sensation of your body being sucked upward, feet first. These are just some of what you may feel – anything and everything is normal.
Visual experiences can occur throughout the practice. You may find yourself in seemingly familiar places, but places you never remember visiting in this life. The same is true of people – you may see people that seem familiar in your practice, but whom you have never met in this life. Vibrant visions; visages of gurus, teachers or guides; nature scenes; colors; light and more may appear during meditation. Again, anything you experience is normal – just notice what you notice.