Continuity mistake: During cocktails, Carrie says "there are 2 type of girls" then two guys in a suit walk by behind her. In the following shot they disappear.
Continuity mistake: Carrie holds the wedding invitation form the upper part, then from the side and then from the upper part again, depending on the shot.
Continuity mistake: After Carrie knocks the chair over, napkins suddenly appear on the table.
Continuity mistake: When Carrie leaves lunch with Big the little rolled paper on the table changes positions between shots.
Continuity mistake: When Carrie cries "Engaged!" her hands are holding her head, but from the opposite angle they disappear.
Continuity mistake: When Carrie says she hates Blood, sweat and tears, Big's hand swaps between being on the table or on the edge of the table or off the table, between shots.
Answer: A popular brand of sexual lubricant. See http://www.k-y.com/index.jsp.
J I Cohen