Continuity mistake: When Carrie gives Berger his sound machine gift, he either holds it by his side or next to his chest, depending on the shot. (00:26:10)
Continuity mistake: When Sam sprays whip cream on the guy, she puts a drop by his right nipple and a bunch around his navel. A shot later, cream appears on the right side of his abs. (00:19:50)
Continuity mistake: When Carrie and Sam walk down the street and talk about Berger's ex, the passers by differ between the wide and close-up shots.
Continuity mistake: Miranda's baby is definitely not the same baby that appeared in the previous episode.
Continuity mistake: When Miranda takes out the strip of condoms, they swap between falling straight to zigzag shape between shots. Also the way she holds them changes between shots.
Continuity mistake: Charlotte says she has to go to the synagogue and one can see Miranda is holding her glass at chest level. From the opposite angle it is by her mouth.
Continuity mistake: Sam goes to flirt with the waiter while Charlotte has a sip. A shot later her arm is already down, without her having lowered it.
Answer: A popular brand of sexual lubricant. See http://www.k-y.com/index.jsp.
J I Cohen