Making a Spiritual Communion
A spiritual communion is not the actual physical reception of the Eucharistic Host which we do so when we approach the sanctuary at Holy Mass.
A spiritual communion is a devotion that we can perform on our own whether we are at Mass and not receiving the Eucharist sacramentally or if we are anywhere else. We may make an Act of Spiritual Communion while watching a broadcast of the Mass on the Internet or even in our morning or evening prayers. 
As His Holiness Pope Pius XII wrote in Mediator Dei, we may make this pious devotion in any place and at any time so long as we do so with “renewed faith, reverence, humility and in complete trust in the goodness of the divine Redeemer,” and so long as we are “united to Him in the spirit of the most ardent charity.”  As a result, through a spiritual communion, we embrace Our Lord as if we receive Him sacramentally.