I've seen actual plume a few times...fwiw, I tend to dig through the cigars with plume to the second level. All it shows is proper storage, it doesn't make the cigar taste any better.
To me it kind of looks like when I get a little too friendly at the strip club...the cigars have a glitter-like shimmer over the entire wrapper where the oils have come to the surface and crystallized.
Found a good pic:
