A nocturnal emission involves either ejaculation during sleep for a male, or lubrication of the vagina for a female. It is also called a wet dream, and is sometimes considered a type of spontaneous orgasm.

Nocturnal emissions are most common during adolescence and early young adult years. However, nocturnal emissions may happen any time during or after puberty. The emission may happen with or without an erection, and it is possible to wake up during the ejaculation, or to simply sleep through it.

The frequency of nocturnal emissions is highly variable. Some men have experienced large numbers of nocturnal emissions as teenagers, while others have never experienced one. 84% of men in the United States will experience nocturnal emissions at some time in their life. For males who have experienced nocturnal emissions the mean frequency ranges from 0.36 times per week (about once every three weeks) for single 15-year-old males to 0.18 times per week (about once every five-and-a-half weeks) for 40-year-old single males. For married males the mean ranges from 0.23 times per week (about once per month) for 19-year-old married males to 0.15 times per week (about once every two months) for 50-year-old married males. In some parts of the world nocturnal emissions are more common. For example in Indonesia surveys show that 97% of men experience nocturnal emissions by the age of 24.

Thomas Alan "Tom" Waits (born December 7, 1949) is an American singer-songwriter, composer, and actor. Waits has a distinctive voice, described by critic Daniel Durchholz as sounding "like it was soaked in a vat of bourbon, left hanging in the smokehouse for a few months, and then taken outside and run over with a car." With this trademark growl, his incorporation of pre-rock music styles such as blues, jazz, and vaudeville, and experimental tendencies verging on industrial music, Waits has built up a distinctive musical persona. He has worked as a composer for movies and musical plays and has acted in supporting roles in films including Paradise Alley and Bram Stoker's Dracula; he also starred in the 1986 film Down by Law. He was nominated for an Academy Award for his soundtrack work on One from the Heart.

Lyrically, Waits' songs frequently present atmospheric portrayals of grotesque, often seedy characters and places—although he has also shown a penchant for more conventional ballads. He has a cult following and has influenced subsequent songwriters despite having little radio or music video support. His songs are best-known through cover versions by more commercial artists: "Jersey Girl", performed by Bruce Springsteen, "Ol' '55", performed by the Eagles, and "Downtown Train", performed by Rod Stewart. Although Waits' albums have met with mixed commercial success in his native United States, they have occasionally achieved gold album sales status in other countries. He has been nominated for a number of major music awards and has won Grammy Awards for two albums, Bone Machine and Mule Variations. In 2011, Waits was inducted into the Rock and Roll Hall of Fame.