the ability to control the senses by drawing them nearer or further away from the sense object itself.
How does one take the senses away from the body and nearer to 'something else'?
It has to be grasped and understood that the senses are not a product of the body, but of the mind. The body can only perceive the senses through the sense receptors (eyes, ears, nose, mouth, etc.). The mind is what tells a human body about the sense experience: dry, cold, sweet, pungent and so forth. Without the mind engaged in the sense object itself, no true experience can be had due to lack of full engagement. One may eat a meal and not taste any of the seasonings because the mind is engaged in talking, for example. One may not fully understand how digestion moves through the colon if that person is reading a book. One may not feel a broken bone in the ribs if there is full engagement while playing football. One may gaze into the flame of a candle in so much to be fully involved in every aspect of that flame and unaware of any needs of the body. These are all examples of the senses being away from the body and nearer to 'something else'. People have a conscious choice to take the senses away from the body at any given time. But it is not the body responsible for this task. Like a car, the body too has a driver: the mind.
How does one take the senses away from all other things besides the body itself?
The mind, also, has the ability to take all of its attention towards the body and all of the inner workings of that body. The same way one can take the senses away from the body, so too one can draw the senses to focus on the body itself. Imagine closing the eyes and meditating on the beat of the heart: What does it feel like? What are the beats per minute? Is the pumping consistent? Is the pump of the heart strong or weak? These are all questions that can be potentially answered by taking the senses inward towards the heart. This is one example of how the senses can be controlled to be engaged in the body.
How does one take the senses away from all other things, including the body?
Let us be reminded, the senses do not belong to the body; they are a product of the mind. The senses are like the antenna and the body is like the television. The signal being received through those antenna (senses) is received because of the mind (like a television network). The antenna allows the television to have a broadcast (experience). In the same way, the mind allows the body to experience the senses and the related object(s). The mind is the senses, and also the base of existence for the senses: the same way the Supreme Self is the base of all things physical and subtle.
In order to rest in the mind, you must become the mind: this is what has been described as resting in the layer of the body called the 'bliss body'. But in order to 'rest' in another aspect of the body that is more subtle, you have to become that part of the mind no longer associated with the body and its senses. When one experiences deep sleep, there is no longer a connection between the body and the senses. All the dreams and experiences had during sleep are a product of the mind. So in this way, one is resting in the mind. But how to do this while awake? The concentration must be improved. It is sometimes heard that one may stop breathing while reading a book because of full concentration and engagement in that activity. The same level of concentration can be applied while turning the gaze inward towards the space between the eyebrows: third eye center. The same level of concentration can be applied, also, while gazing at a flame of a candle.
Mastery of pratyahara can lead not only to great concentration, but also to deeper levels of meditation. One that controls the senses by withdrawing or going near to sense objects, eventually, controls the mind and its activities:
but only because of the mind...
For some small tips on meditation, visit here: http://theseventhlimb.blogspot.com/