"Mane nobiscum, Domine." "Stay with us Lord" is what the disciples on the road to Emmaus asked Jesus. Later at supper Jesus did something even better. In the breaking of the bread he stayed in them.
Imagine going to church with a non-Catholic friend who doesn't know what the Mass is all about. You tell your friend that the people going to Communion will receive God into their bodies.
"Wow!" says your friend. Then your friend then asks, "How can you tell this is really happening? How will the people respond to this miracle?"
You have to think about it.