The act of
having sex with another person in order to wish said person good fortune.
usually done before exams, departures, or future confrontations with someone/
something. Plus it rhymes. :)
Rndm Chick: Fuck, I'm totally gonna fail my driving exam
tomorrow.
Boyfriend: Well I think you'll do fine, but a good luck fuck couldn't hurt right? *
5 Minutes Later* Rndm Chick: Im so failing....