Mostly in NZ in just means a longer drawn-out massage with some extra licking, touching. A way of saying it's not just a basic rub down.
I booked a Dongguan massage at the Spa of a nice hotel I was staying at while travelling. It was a 2 hour experience with hot cloths, different massage tools, oils, gels, a long foot and leg massage; A long drawn-out experience designed to totally rejuvenate you. (It was Undies only with the white cotton cloth draped over, but nothing sexual. It may have been available but I wasn't wanting it)
Well worth it, it feels fantastic, especially if you have had long flights.