Take the "adult" pools at the various casino resorts, with their "European" or "Brazilian" (at the Rio) experiences. Translated, that means "bare titties." The pools are heavily, and sexily, advertised everywhere, and raise barely an eyebrow. The Pond at Green Valley Ranch has the best ad I've seen:

No, I haven't been, and I probably won't until I have washboard abs — which is to say, like, never. (And if it's skinny dipping, why does she have clothes on? Not that I mind the heels.)
Green Valley Ranch is actually out in the suburbs, so I'm a little surprised they've got the naughty pool. I'd just assumed those were reserved for the raunchier Strip-area properties. Sadly, the truth about these places looks a little bit more like what's delicately called a "sausage festival," at least according to this photo in a recent Las Vegas Weekly:

Not quite what I had in mind.
Thing is, this stuff is everywhere. Like, at the shuttered-for-now Lady Luck casino, there's this sign:

See? They'll be back soon. Which of course calls for a picture of a naked lady's back. Makes perfect sense.
But my favorite out-of-place, wacky, sex sells example is off the beaten path a little — it's in the industrial part of Main Street, a bit south of all the downtown lights:

Look, if I ever do need bail, it's going to be BECAUSE of a girl dressed as a slutty cop. Who's wearing heels.