"Then the Priest, with the Minister, say the psalm, Judaica me, with Gloria Patri, at which he is to bow his head to the cross. Then he repeats the Introibo, making with his right hand the sign of the cross from the forehead to the breast. Then he bows his head and body to the altar and there he stands bowing till the Minister saith, Misereatur. When he saith, Mea culpa, he smites thrice upon his breast with the right hand; and thus the Missal proceeds in its ceremonies in all the remaining parts of service."
Now, I'm tagging My sister, Marsha.