A One-Night Stand is where two consenting adults who are mutually horny agree to engage in coitus. One-Night Stands are only defined as such when the tryst lasts ONE night...no repeats! (otherwise we have casual sex). One-Nights Stands typically involve sprucing up, clubs/bars, copious amounts of liquor, great sex without small-talk, and driving away or leaving after sex.
Woman: "Want to head to my place?"
Man: "Sure, not looking for anything serious right now, just a One-Night Stand."
(great sex follows arriving at his/her place, girl or guy gets up to get dressed.)
Man/Woman: "Have a great night."
Man/Woman Reply: "You too."
(get in car and go home.)