I don't care if all of this vocabulary of NYC's best bars is made up (it sure sounds made up), I still loved reading it. You can totally tell which places are about the drinks, which are about hospitality, which are bitchy, and which are all about the benjamins.
Sipper: A small pour (typically Mother's Milk) gifted to a colleague, loved one, regular, etc.
Amuse-booze (experimental term): A tiny sipper to acknowledge a guest an reassure them they will be served soon.
The Cousins: Affectionate term for other cocktail bars (after the British secret service's name for the CIA in Le Carre's Smiley novels).
Even if it's fake, it's real.