I don’t suppose many spankos get the pleasure of a wedding at which there isn’t at least one innocent maiden auntie who must not be scandalized. But if any do, this cake topper (found at Nothing Random About A Spanking) is surely the one to use:
"...the girls are prepared in the reformatory’s punishment room, naked, lying on their backs on special benches, bound with their legs spread above their heads, shamefully showing the two holes usually hidden..."