La petite mort = little death

La petite mort (French pronunciation: ​[la p(ə)tit mɔʁ]; "the little death") is an expression that means "the brief loss or weakening of consciousness" and in modern usage refers specifically to "the sensation of post orgasm as likened to death."[1]

The first attested use of the expression in English was in 1572 with the meaning of "fainting fit." It later came to mean "nervous spasm" as well. The first attested use with the meaning of "orgasm" was in 1882.[1] In modern usage, this term has generally been interpreted to describe the post-orgasmic state of unconsciousness that some people have after having some sexual experiences.

https://en.wikipedia.org/wiki/La_petite_mort