What does affusion mean?
The definition of affusion
Af*fu”sion, n.
Etym: [Cf. F. affusion.]

The act of pouring upon, or sprinkling with a liquid, as water upon a child in baptism. Specifically: (Med)
The act of pouring water or other fluid on the whole or a part of the body, as a remedy in disease. Dunglison.