An Act of Spiritual Communion. When unable to receive Holy Communion, one could make a Spiritual Communion. This is a prayer in which we ask our Lord to come to us in the same way He would if we were able to receive the Sacrament.
My Jesus, I believe that You are truly present in the Holy Eucharist. I love You above all things, and I desire to receive You into my soul. Since I cannot at this moment receive You sacramentally, come at least spiritually into my heart. I embrace You as if You were already there, and unite myself wholly to You. Never permit me to be separated from You. Amen
St. Alphonsus Liguori (A.D. 1696-1787)