According to Osho, we usually cannot feel disidentified with the body because there is no gap between doer and doing: the body obeys our will, so mover and moved seem one. Identification rests on control. When the body moves autonomously, a gap appears and consciousness naturally becomes a witness, revealing our separateness.
Because your body usually does what you tell it, you feel like it’s you; only when it moves on its own can you notice you’re the watcher, not the body.