Continuity mistake: After Samantha reads Big's birthday note, her cup of coffee swaps between being next to her mouth to flat on the table, depending on the angle.
Continuity mistake: When the counselor tells Sam to play sexual games her boyfriend's hand is away, but a shot later it's suddenly on her shoulder.
Continuity mistake: When Sam's boyfriend says "our sex life is diminished" his hand is on her right shoulder. A shot later it's on her left shoulder.
Answer: A popular brand of sexual lubricant. See http://www.k-y.com/index.jsp.
J I Cohen