As I understand the Lutheran concept of consubstantiation, it is because of the divine nature of Christ that His human substance is found in the Eucharist. The divine attribute of omnipresence is communicated to the human nature of Christ like the heat from a red hot iron would be transferred to something it was placed near. So, when one eats the bread and drinks the wine, they are actually chewing the body of Christ and drinking His blood.
But if Christ's human substance is now omnipresent, wouldn't that mean we also breathe Christ and type on Christ etc? Or is it just when the elements are consecrated that His substance is put in them?