It is a state of total calm. There is no activity. You are experiencing here moments of relaxation. But what it should actually include is the complete relaxed state of not just our Bodies but also our minds.
The sensation of real tranquility, is feeling your body to the very core of who you are. There is no more stressand you are able to relax into every fibre of your body.
Remember that feeling of tranquillity is not something you achieve by doing things, but by letting things go. Give yourself some quality time and let the mental peace be there. Taking care of your own self should always be on the top of the priority list.