Flirting with or
hitting on your good friend's very serious
girlfriend. Named after "Koon" of youtube fame. Kooning is often made possible when the boyfriend is away and the
girlfriend shows pity for the kooning boy which is misinterpretted by the desperate despicable kooner as affection. Kooning is not cheating because the girlfriend is very pleased with her current boyfriend which just makes kooning all the more despicable.