When I'm the one to offer the Mass I ask him if he will have Holy Communion, and then I make a detour on my way to the extraordinary ministers to attend to him. Yesterday, for whatever reason, I guess he didn't expect me to come back with the Precious Blood. When he realized why I was in front of him and what I was holding, he reached up quickly and snatched the skullcap from his head. The action struck me in its automatic necessity. He found himself, all of a sudden, in the immediate presence of the Precious Blood, and so had to uncover his head. He just did it, and probably didn't even need to think about what he was doing. It was like second nature, or perhaps better, grace having built on nature.
I wish I could bottle up some of that second nature--the sense that the presence of the Lord in the Sacred Species demands a particular decorum all its own. So much of that sense seems to be lost, at least from where I stand as a minister of the Lord.
Just for fun, here's the skullcap section from our old Manual of Custom:
Priests who have completed their studies are allowed the use of the plain black skullcap. [per the universal custom of the Roman rite] It may not be worn by clerics or brothers without necessity and permission of the Minister Provincial. The skullcap is removed on entering, leaving, or passing through the choir of the church. It is taken off during Divine Office, whenever a genuflection, whether simple or double is made, while the gospel before the homily is read, while saying the Confiteor, the the Preces, and during the orations, at the final antiphon of the Blessed Virgin, a the Sacrosanctae. A priest who reads or chants the Invitorium, lessons, short responses, antiphons, martyrology, uncovers the head during such reading or chanting. The skullcap is also removed at the Asperges before the Mass on Sundays, during the Kyrie, Gospel, Credo, intercessions and from the Sanctus to the Communion of the priest or faithful inclusively, and when the blessing is given at the end of Mass. It is also removed during the exposition of the Most Blessed Sacrament, when receiving the Pax, in processions in which the Blessed Sacrament is carried, when going to confession, imparting blessings with relics, or receiving a blessing. It is likewise removed during the reading of the blessing of the Rule and during the blessing after the Lent of Benediction.