Continuity mistake: When Carrie and Aidan are in bed together, he hands her the second picture and she holds it with two hands. A shot later she is holding it with one. A couple seconds later she finally grabs it with both.
Continuity mistake: When Carrie leaves the bar, Shayna extends her arm towards the peanuts, but half a second later they're crossed.
Continuity mistake: When Miranda lies on the rug, the phone is next to the upper part of the rug. When the shot changes, it lies on the middle part, away from the rug.
Continuity mistake: When Sam runs towards the cab, the passers by are not continuous between shots.
Continuity mistake: When Charlotte says she wants to quit her job, her hands are on the table. A shot later they are lowered. (00:02:45)
Continuity mistake: When the waitress brings Charlotte's breakfast, a shot later the waitress is magically gone, Charlotte's hand is on the mug and, last but not least, the blue napkin disappears.
Continuity mistake: When Miranda says "that's a big maybe" Sam is drinking coffee, but a shot later her arm is lowered. (00:02:12)
Continuity mistake: During breakfast, when Carrie says she "worked harder than her SATs" Sam's mug is close to Charlotte's bowl, but a shot later Sam is holding her mug, This swaps back and forth.
Continuity mistake: During breakfast, when Sam says "Honey, he's a keeper", lighting screens are reflected on her sunglasses.
Continuity mistake: When Miranda talks about her date licking her butt, the food on her fork disappears between shots.
Continuity mistake: At the store, Tricia's daughter is looking at the left or straight on, depending on the angle.
Continuity mistake: When the girls are drinking Martini, Miranda lowers her glass twice.
Continuity mistake: When Carrie confesses Charlotte that she is calling Aidan, the dancers moving and waving their arms wildly behind Charlotte disappear between shots. One might argue that it's because of the angle of the shot, but they're all moving around all the time and at least their arms should be visible.
Continuity mistake: During dance class, when Carrie confesses she calls Aidan, the same woman walks behind her twice.
Continuity mistake: During dance class, when the teacher says "every movement has a meaning" Carrie's right arm is down or raised depending on the shot.
Ghost town - S4-E5
Continuity mistake: The bite on the cake changes all the time between shots.
Ghost town - S4-E5
Continuity mistake: When Sam says she'll go to the inauguration, the invitation lies between both tables but a shot later it is just on one table.
Ghost town - S4-E5
Continuity mistake: During diner, when Miranda talks about the ghost and says "I've been living there...", her hands are holding the glass or not, and extended or not depending on each shot. No continuity in any.
What's sex got to do with it? - S4-E4
Continuity mistake: When Charlotte is showering, a bunch of foam on her forehead appears and disappears and reappears again randomly depending on the shot.
Continuity mistake: The musician leaves a note for Carrie on top of the napkin. A shot later the napkin is inches away and the note is on top of the glass table.
Answer: A popular brand of sexual lubricant. See http://www.k-y.com/index.jsp.
J I Cohen