I honestly think it's a hard variation of the word 'fuck' to make a logo for; for a porn site anyway.
You're offering a much better prize than most others...
Maybe giving some ideas of very basics.. like feel and style you'd like to see..
I have ideas myself, though I don't have time to do them myself. If you want to ICQ me, I can let you know / show you privately.. it'd probably win the contest.. I'd just need someone else to do a certain part of it. ICQ is 129060301 .. Hit me up 
Matt