He mentioned me by name here, though I'm not a Liturgical expert. Perhaps Elwin could chime in.
I would guess that the pinky fingers are just the initial contact where the priest is just barely entering the space of the altar, effectively asking permission to enter the "Holy of Holies", admitting that he is unworthy to enter but then entering while relying upon the relics/merits of the martyr. Just my guess that it's something like that, where the tips of the pinkies just represent the minimal entry required to make the request to enter.
So the priest starts at the foot of the altar, after confession and absolution can climb the steps, and then admits his lack of merits to enter the inner altar, the Holy of Holies, finally relying upon the merits of the martyr to enter.