Perving glasses

Closely related to sunglasses, perving glasses are purchased for the intended use of spying on sexy girls without their knowledge. Perving glasses have dark lenses so that the user can see out, but nobody can see where their eyes are looking, making them ideal for scoping out hot ass and not having to look away when the owner of the hot ass looks at you. They are best used when facing parallel to the girl, while not facing directly at her. The eyes can then rotate in their sockets to focus on the fine details of the girls body.

Perv glasses are basically sunglasses with reflective lenses. Which means that people cannot tell if you're looking at them or not, because they can't see your eyes. Some people use these types of sunglasses to avoid an awkward situation with someone. For example, if a student happens to see a teacher outside of school, they'll pull out their sunglasses, put them on, and just do what they can to avoid him/her. Pretty simple operation!