perhaps, Ms Jet, titled this thread with Her tongue-in-cheek -- which is exactly where i'd like my tongue to go -- albeit perhaps not the same anatomical cheek.
but since MissBStar asks: "Can Domme's be Nude or offer their Cocks\Vagina's to their slave?" i shall answer: unequivocally -- yes.
the operative word here being "Can". not "will" they or "do" they or "must" they -- but "Can" they. as btmbob3 suggests, they "do pretty much what they want". a Domina who allows others to predetermine which of Her many weapons She may wield in expressing Her dominance is no more a Domina than the "hookers with a whip" so often decried at sites like Max Fisch. in fact, the near-impossible dream of the slave that his Mistress might indeed reward him with a glimpse, if not a touch, may well be the key to unlock his imaginative subspace adventure. again, not that She "will", only that She "can"--and if he's good enough, maybe, just maybe, someday, She "might".
and though many may choose to keep that particular weapon sheathed, in the specific case of the divine Ms Jet, for it not to be wielded would be a sin, a waste -- hell, it'd be a downright tragedy.
so thank You, Mistress Jet