Where do you end?
What delineates the borders of the entity that you are? The immediate answer seems to be that the senses occupy the role of translating to the ‘you’ entity what is in the immediate proximity of the ‘you’; literally what you are brushing up against, or smelling, or tasting, or hearing or what you are seeing.
These are the ‘places’ where we reside, or at least they are places worth identifying with some of the time, along the borders of the self, where the self meets the non-self. It is within the place of contact between the perceptual organs of the human and the world that is the appropriate place for the individual to vest their self-identity. The more one sees oneself as the dance between self and non-self the more deeply one can live in the moment drawing from it what it offers.
If we invest our sense of self in the sense data, we find an expansion of self not a diminishing. We are all that our sense data perceives. We are our partner while our sense organs rest upon them we are the floor, and the air through which we fly, we are the skies that we breathe into, and the water that we excuse ourselves to drink.