Trivia: There is a Spanish language remake of this series called "Metástasis" that takes place in Colombia. Interestingly, Colombia has a highly successful mixed private/public healthcare system that covers around 97% of its population, which runs contrary to Breaking Bad's premise that Walter White becomes a drug kingpin in order to pay for his cancer treatments and ensure his family's financial stability, due to the United States' for-profit healthcare system.
Trivia: For most of season 2, Skyler is pregnant, but Anna Gunn (who plays Skyler) was not. The opposite is the case for the character of Marie: Betsy Brandt (who plays Marie) was pregnant during season 2, even though Marie was never pregnant during the show. In an episode early in season 2, we see Skyler rubbing lotion on her belly. That is Betsy Brandt's pregnant belly standing in for the close-up shots.
Chosen answer: It is part of the ritual for la Santa Muerte. It is a sign of humility and sacrifice.
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