"Pearl necklace" is a slang term referring to a sexual act in which a man ejaculates semen on or near the neck, chest, or breast of another person. Such ejaculation can follow mammary intercourse, fellatio, intercourse, or masturbation over the other person. The term originates from the way the deposited semen resembles a necklace of translucent white pearls.
Making a pearl necklace is an activity that sex workers use as safe sex alternative for people who prefer not to wear condoms.
Pearl necklace (sexuality) Wikipedia
The term was used by George Carlin in his "Incomplete List of Impolite Words" joke as early as 1984 on the album Carlin on Campus.
The term was introduced to viewers of the HBO sex comedy Sex and the City in episode 69, first broadcast in 2004. In the episode one of the characters misunderstands a promise she overhears made to another character, Samantha Jones, who then explained the term. Boogie-Blues band ZZ Top was criticized for the lyrics of its song "Pearl Necklace" as one of its songs whose lyrics were claimed to objectify women.