The act of masterbation while watching a reflection of yourself preform the act. Most commonly this is purpotrated in a hotel room in front of a mirror.
*door opens*
Connor: So Craig what are you doing in...OH MY GOD! WHAT THE HELL?
Craig: I was, eh, um, er...
Connor: YOU WERE WANKING OFF TO YOUR OWN REFLECTION!
Craig: I was just...er...
Connor: That was a Valkenburg Mirror you sick...I MEAN FOR FUCKS SAKE WHAT YOU WERE THINKING?!
Craig: Um...
Connor: So Craig what are you doing in...OH MY GOD! WHAT THE HELL?
Craig: I was, eh, um, er...
Connor: YOU WERE WANKING OFF TO YOUR OWN REFLECTION!
Craig: I was just...er...
Connor: That was a Valkenburg Mirror you sick...I MEAN FOR FUCKS SAKE WHAT YOU WERE THINKING?!
Craig: Um...
by Mark Murray - WOW Champion December 22, 2008

A mirror above a toilet that is low to the point where you can actually see your Johnson working its magic. Also applicable if the mirror only shows ones face, and if you make silly faces while you go pee.
by AdmiralSpiffy July 5, 2009

When you are high on psychedelics and you find yourself looking into a mirror. What will happen is a strong gravitational pull from the mirror holding you in place, eyes locked to your own eyes, that takes a strong physical effort and will power to break. You may or may not come to a profound realization.
"Bro, you were the bathroom 20 minutes are you okay?"
"Yea man, I went pee then got mirror locked washing my hands."
"Yea man, I went pee then got mirror locked washing my hands."
by Zenoren April 17, 2020

When you look in a mirror or someone tells you you you’re drunk and you instantly feel that much more drunk
by Yungswaggs November 9, 2020

A mirror in the homes of fuglass attention seeking ho's who don't realize they're not as hot as they think they are
by Whateverkumar June 24, 2022

a type of Rubix cube but with no colors. Though you would think that it could be easy to solve, you are clearly mistaken, it has different shapes that when soling you have to try to get back into the square shape it origonaly was.
Person 1:Hey have you heard of a mirror cube
Person 2:no what is a mirror cube
Person 1: its hard to explain
Person 2:no what is a mirror cube
Person 1: its hard to explain
by bri1234567890 January 28, 2023

a type of brain cells that are activated both when an individual performs an action and when they observe another individual performing the same action.
you see someone smile, your mirror neurons activate, allowing you to experience the feeling of happiness or joy that the other person is experiencing. Similarly, when you watch a skilled athlete perform a complex movement, your mirror neurons activate, enabling you to understand how the movement is performed and potentially allowing you to learn the movement yourself through imitation.
by bbniyo March 9, 2023
