Continuity mistake: When Sam talks about sperm taste and Charlotte leaves, Sam grabs the mug's handle, then from another angle her arm is down, then back to a front shot and she is holding the handle again.
Continuity mistake: When Trey's mom asks Charlotte if she plays tennis, she takes out a cigarette. She never lights it (nor do we hear any sound), but half a second later it is already lit up.
Continuity mistake: When Trey's mom orders the cheese nibblings, Trey's arm swaps from lowered to drinking from a glass.
Continuity mistake: After meeting Big, while ordering food with the girls Carrie closes her menu twice. (00:08:14)
Continuity mistake: When Carrie holds the menu she either has her right arm down or holding the menu.
The big time - S3-E8
Continuity mistake: When in the ladies' room, Sam is painting her lips with the brush and says "he's in blue ball hell" then the brush is away and she is using her finger, instead.
The big time - S3-E8
Continuity mistake: While on the boat party, Carrie brings a drink to Charlotte and as cruise suddenly appears out of nowhere behind her.
The big time - S3-E8
Continuity mistake: While in bed with Aidan Carrie's left arm position has no continuity between shots, specially when she toys with his necklace with her right hand but a shot later it's the left hand.
Continuity mistake: While Charlotte has dinner with a couple, he has his arm around her shoulder, leaving no gap in between them; yet from the angle behind there is a gap.
Continuity mistake: When Charlotte is talking during breakfast her left arm is either still on the table or moving.
Continuity mistake: When the breakfast scene starts, Sam is either drinking from a straw or holding her drink away, between shots.
Continuity mistake: After spilling the sauce on the floor, when Miranda is discussing with her boyfriend her bag suddenly disappears from her shoulder. Later on it magically appears on the floor.
Continuity mistake: When Miranda drops the paper bags on the floor a lettuce and a bottle of water fall out. Seconds later the stuff changes completely: The bottle is gone, the bags are in a different position and, best of all, Miranda's leather bag (which was previously hanging on her shoulder and suddenly disappeared between shots -listed mistake-) magically reappears on top of the mess.
Continuity mistake: When the tomato jar crashes on the floor, the splatter changes shapes between shots and the label disappears in the second shot.
Continuity mistake: Baird puts a sock inside Charlotte's crotch and her tie gets skewed. A shot later it's straight.
Don't ask, don't tell - S3-E12
Continuity mistake: When Miranda blind dates Dwight Owens, he puts the beer on the table twice.
Continuity mistake: When Aidan shows the chair to Carrie he raises his right arm. A shot later it's down.
Continuity mistake: Miranda arrives home and starts opening an envelope. From the opposite angle it is already open and she is already holding the letter.
Continuity mistake: When Carrie and Miranda are eating pink muffins, Miranda's cup in her hand suddenly vanishes.
Continuity mistake: When the chef comes to greet the girls a waiter in a yellow and red shirt is in the back waiting a table. A shot later he is several meters ahead, close to where the chef is.
Answer: A popular brand of sexual lubricant. See http://www.k-y.com/index.jsp.
J I Cohen