The reasons are not our business, but we remain generous enablers—so you should know the dark basement bar dubbed The Association is now open downtown for your nights requiring discretion. (Or indiscretions.)
Down a few steps and through a door marked only with "110" (the street address), you'll find a large underground space with very few lights but a lot of leather. If your reasons for visiting are on the up-and-up, and you just want to come by after work for a stool and a Vesper Martini (gin, vodka, splash of Lillet), the doors open at 5pm on weeknights—and they'll serve low-key small plates (cheese, charcuterie) for a couple hours.
Later, though, you'll probably want to head for the corner furthest in the back—past the lamp scored on eBay, over the carpet scored from a Vegas casino—where you can really get to know the classic cocktail menu, and your mysterious plus-one, in peace. (The owners operate a few of your other favorite no-questions bars—Bar Copa, the Room and Coda.)
But if all this puts you in the mood for a French dip (no, the other kind), you're right next door to the new but very old Cole's.
Where of course you'll be guilty, by Association.