What is the body? Not the picture of it but the direct experience of it. Referring to instructions given in the Ānāpānasati Sutta, guidance is given to directly experience the body in its diverse manifestations of energy, feeling and sensation. Breathing in, breathing out, allow the process to occur at its own rate and stay with what’s unfolding for you.
Dhamma practice is the channel for direct experience: that which is entered through the door of feeling. This is not the ‘mental’ knowing: the somatic sense responds to feeling. Your place of practice is this direct ‘feeling-knowing’ – pājānati – through mindfulness of the body.