Bust a nut is a slang term used to refer to ejaculation. "Nut" is another slang term for a testicle, so "bust a nut" is a crude way of referring to the release of ejaculate. An alternate meaning for the term means to work very hard at something or put in significant effort. As such, bust a nut may refer not only to ejaculation, but the implied effort leading up to it.
This expression is believed to have emerged in the 1930s. Its use in a sexual context was popularized in the 1980s as a result of its use in rap and hip-hop songs.
The term "nut" got its time in the spotlight in 2014, when a series of memes called "when you nutted but she still sucking," circulated widely on social media platforms. The meme showed images or animations of people expressing a combination of shock, pain and pleasure and suggested a sexual situation in which oral sex continued following orgasm, an act that could be referred to as post-orgasm torture.
