I don't think you need a sex drive to post dirty thoughts. More likely your dirtier thoughts don't appear that remarkable to you.
I dunno if fantasies are all that important. I can tell you that I would be willing to consider any activity concievable. (This is not just limited to things like fucking a female version of Gordon Freeman while wearing a Freakazoid outfit covered in edible blue body paint. It can also include things like participating in "Spring Time for Hitler.") However, I would prefer to schedual life risking activities, (like being hung upside down with a hook through my testicles just as I climax) for sometime when I plan to die. I have no ethical or moral problem with those kind of fetishes(can't say they sound like they would be fun), but often there is a... minor flaw in them. You can only do them once.
This is not to say I would automatically be willing to do those things. I would be willing to consider them. And I bet you could probably talk me into a lot. If I could get decent proof that I would catch no inconvenient incurable plagues from doing it, or suffer irreperable damage turning me into a vegatable until somebody has the decency to unplug me, I bet you could talk me into trying it.