Perv Shading
The act of observing a member of the opposite sex (or same sex depending on your preference) via a pair of highly reflective shades so as to hide ones intentions.
Joe was perv shading with his aviators that he found at the festival.
Perv shades
Sunglasses that, when worn, make the person's eyes impossible to see. Used to look at boobs, etc.
Damn, that girl's hot, I wish I had my perv shades with me.