Law of Skins

Pertaining to the British show Skins, this law dictates that any two characters in a drama of a sexual nature shall, at some point in the current episode or next, engage in intercourse.

*Tony and Effy appear on screen*
Guy 1: "They're gonna bang"

Guy 2: "They're related!"

*Later in the episode "Now fuck your sister!"*
Guy 1: "Law of Skins!!!"

law of new skin

is a theory that no matter how hot or sexy your current piece of ass is, the girl you haven't slept with yet is more desirable

you are currently in a relationship with a 9.2.
but you really wanna bang the 6.7 with the crooked teeth at the end of the bar.
The law of new skin says that you will sleep with the 6.7