Other mistake: When the girls are at a restaurant right after Carrie leaves the Hamptons, Charlotte picks up her glass and puts her mouth on the straw as if she's drinking, but the liquid in the glass doesn't budge.
Continuity mistake: While at their friends' place, Carrie holds her glass of wine wth her index finger extended over the bowl. A shot later the grip has changed completely.
Continuity mistake: When Charlotte arrives to visit Sam, the doorman is facing straight and turns his head to the left. A shot later his whole body has turned to the left.
Continuity mistake: At the party, when Samantha is talking to Sean, she holds her glass at breast level, but when his wife arrives it is at mouth level.
Continuity mistake: When Carrie and the guy kiss at Central Park a man in a gabardine walks by fast but disappears in the following shot. Then he reappears seconds later walking slowly.
Continuity mistake: When Peter's wife asks him if Carrie saw his d*ck, he has a mug in his left hand. A shot later it disappears and his arm is lowered, only to reappear in the following shot.
Continuity mistake: When Carrie bumps into naked Peter, his right arm is lowered or raised scratching his ear, depending on the shot.
Continuity mistake: When Carrie is at her friend's place in the Hamptons her left arm is either on or off the table depending on the shot.
Answer: A popular brand of sexual lubricant. See http://www.k-y.com/index.jsp.
J I Cohen