In theory, the only thing that keeps our consciousness in our bodies is the self-awareness of being here. In the body, caused by our physical senses. Vision, balance, feeling, hearing- all of these senses, and the proprioreceptors in our brain tell us 'where' we are when we are awake and aware. But when you enter the trance state these senses start decreasing until they are effectively 'offline'- and then our consciousness is not receiving constant feedback about 'where' it is, or 'should' be, and is free to move out of the body.
The trance state is the state in which this is happening without losing consciousness- while we are awake but our body is, for all practical purposes, asleep.
The tactile feelings you describe are symptoms of trance, but be aware, that if you are constantly 'feeling for change of sensation' in your body, you are centering yourself in it. I would wait for symptoms, such as strong vibrations that are now diminishing, or visions and voices or noises as signposts that it is time to start doing an exit technique, such as the rope technique.