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.
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.