Continuity mistake: When Alek is ordering a burger, the way his hand is bent against his face differs between the front and back shots. After he says "Absolutely!" his hand is lowered, then it's raised again.
Continuity mistake: When Carrie unties the knot in the parcel, all corners of the ribbon differ in style and length between the wide and the close-up shot.
Continuity mistake: On the way to the opera, when Alek stops to watch the musicians, Carrie stands perpendicular to him. A shot later they're both parallel in front of each other.
Continuity mistake: When Steve's foot gets stuck in the gum, the passers-by are not continuous between shots.
Continuity mistake: When Miranda's plastic bag breaks open, the stuff gets scattered all over the curb. A shot later it's all piled right next to her foot.
Continuity mistake: There's a scene that opens with Carrie and her boyfriend in his apartment, and he's sitting with baby Brady on his lap. The camera cuts to another angle, and it's very obviously a different baby.
Answer: A popular brand of sexual lubricant. See http://www.k-y.com/index.jsp.
J I Cohen