As a young girl, my classmates and I were also taught by the nuns to strike our breast at the Elevation of the Host during the Consecration (prior to the Vatican II Revolution) while repeating the words of St. Thomas, "My Lord and My God". At the Elevation of the Chalice, we were to again strike our breast while repeating, "My Jesus, Mercy". After the Revolution, we were advised to refrain from making gestures, including the Sign of the Cross. Naturally, the clerical revolutionaries wanted all gestures which signalled humility and contrition to be done away with.
I notice that we older Traditional Roman Catholics continue to strike our breasts during the Sanctus, Consecration, and the Agnus Dei. The younger crowd usually refrain from making gestures except after receiving Holy Communion. Many of them make the Sign of the Cross when exiting the Altar rail. The nuns trained us to make the Sign of the Cross after making our thanksgiving for the Holy Eucharist in the pew.
Something else which I find very interesting: The older people continue to genuflect every time we enter or leave the pew and to perform a double genuflection if for some urgent reason we must exit the pew after the Consecration. The younger people, especially the young girls from our local SSPX school, rarely bother to genuflect.