Āsana is a widely known word in yogaland, meaning seat, but in more recent times has come to be a term for a 'pose' or 'posture'. In the philosophy of Kaśmīr Śaivism they have a different take on it, which predates Haṭha yoga's ideas on āsana. This ties in with the previous post and 'being still at the platform as we watch the trains pass' to see reality (opposed to viewing the train from another train).
The difficulty always is describing that which is beyond words. As soon as we use words it creates an object, which it is not. The closest we can get are pointers, proximities and metaphors. (Please also note, in the video the Sanskrit pronunciation is not accurate.)
To put the video into a (living) metaphor which is commonly used by teachers- we are given an insight into the nature of consciousness every night. We fall asleep and we dream. In the dream, the character in the dream (who is us) feels as if all is real; moving around the scene; thinking; feeling; perceiving. Yet the dreamer never moves. We then 'awaken' in the morning, but fall asleep to consciousness by using the mind to focus on objects. The objects give us the perception of time and space, but ultimately separation too. If that focus is turned around, all changes.
Another way to think of things, and we are not far away from this it seems- VR is getting more impressive by the day, so I don't think it will be long before this is in creation- Imagine a VR suit (which we'll call the body) and a computer (we'll call the mind). You are just sat in the living room, but this suit and computer combined create all the sensations of you moving through a computerised world with the most incredible graphics. When the game ends, you are still there, sat in your chair.
That is the nature of consciousness.
It is really no surprise that we are not far from creating that. We are consciousness, so in 'time' would follow consciousness's nature, whether it is realised or not. It's like consciousness wants to create consciousness to show us consciousness! When we know we are effectively in that VR game all is peaceful, until we get too engrossed in the game. Anyone who has played computer games will recognise this experience. Yet this is also the nature of Being.