When priests and believers recite the Trinitarian invocation with which Mulligan blesses his breakfast, "In nomine Patris et Filii et Spiritus Sancti" (“In the name of the Father and of the Son and of the Holy Spirit"), they often make the "sign of the cross" with their fingers, either in the air or by touching successive parts of the body: forehead, chest, shoulders, or forehead, lips, chest. (Grammatically, Mulligan's "Spiritus Sancti" should be the genitive "Spiritui Sancti," but Spiritus is heard often in liturgical settings.)

JH 2017

Mosaic of Christ making the sign of the cross, in the Byzantine basilica of Sant'Apollonare Nuovo in Ravenna. Source: Wikimedia Commons.