Looking a erotic pictures or reading erotic fiction to get yourself wet and then patting the pussy lips or smacking your labia lips.
AKA mat slapping
Girl home alone txt's boyfriend:' Hey babe send me some pornographic pictures of yourself please"
Boyfriend txting back:"Why hun you missing me?"
Girl: "Errr yes missing you lots need to do some mat smacking"
Girlfirend: "masturbating, bean flicking you know Mat slapping!"