It is the custom in Anglican Catholic churches, when the priest or ministers are sitting at the sedilia during readings or singing, for the priest to turn back the foot of the chasuble on his lap so that he then rests the palms of his hands on the lining, and not on the fabric, of the chasuble. Deacon and Subdeacon do the same with dalmatic and tunicle. Thus sweat (or, at the blessing of incense before the Gospel, incense or charcoal) cannot not mark the vestment. My recollection is that this goes back to preconciliar custom; evidence is available in the ancient marks of two sweaty hands on the linings of the vestments in High Mass sets in sacristies all over England.
I have never seen this done in RC Masses, whether OF or EF. Is it an Anglican idiosyncrasy?