On Orchard Road in Singapore, which is like 5th Avenue in NYC, there is a small building that was constructed in the 1970s and is referred to by locals as Four Floors of Whores. I was taking a stroll down Orchard one evening, not knowing that this existed, and on the street I was politely approached by at least four young attractive women within the block.
The building contains numerous massage establishments and bars. It seemed to be a sort of working man's paradise. If you want something more discreet and upscale, then visit almost any spa in the main business district.