Spiritual Communion

According to the Cure of Ars, aka the patron saint of parish priests, "A spiritual communion acts on the soul as blowing does on a cinder-covered fire that was about to go out. Whenever you feel your love of God growing cold, quickly make a spiritual communion."

Say this prayer, written by St. Alphonsus Liguori in the 18th century, in place of the bread and wine: 

My Jesus, I believe that you are present in the most Blessed Sacrament. I love You above all things and I desire to receive You into my soul. Since I cannot now 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.