Knapplöst knull
Alltså; uttrycket knapplöst knull (zipless fuck) kommer från Erica Jongs bok Rädd för att flyga och betyder enligt henne:
"A sexual encounter between strangers that has the swift compression of a dream and is seemingly free of all remorse and guilt. It is absolutely pure, there is no power game and it is free of ulterior motives. It has also been described as the perfect one night stand".