Continuity mistake: When Seth tells Carrie that Dr. G's plant is plastic his hand is either holding the glass or not. This changes back and forth.
Continuity mistake: When Carrie talks about his first date with Seth there's an aerial shot of him holding a drink and taking a sip. A shot later he is not holding the glass.
Continuity mistake: When Stanford tells Carrie that she has to have a shrink, a man suddenly appears behind and the kid next to him changes positions between angles.
Answer: A popular brand of sexual lubricant. See http://www.k-y.com/index.jsp.
J I Cohen