Wet dreams

A nocturnal emission is an ejaculation of semen experienced by a male during sleep. It is also called a “wet dream”, an involuntary orgasm, or simply an orgasm during sleep.

Nocturnal emissions are most common during teenage and early adult years. However, nocturnal emissions may happen any time after puberty. They may be accompanied by erotic dreams, and the emission may happen without erection. It is possible to wake up during, or to simply sleep through, the ejaculation in what is sometimes called a “sex dream”. Women can also experience orgasms in their sleep.

Spermatorrhoea
In the 18th and 19th century, if a patient had involuntary orgasms frequently or released more semen than is typical, then he was diagnosed with a disease called spermatorrhoea or seminal weakness. A variety of drugs and other treatments, including circumcision and castration, were advised to treat this “disease”. Some modern doctors, especially herb healers, continue to diagnose and advise treatments for cases of spermatorrhoea, but these treatments have not been validated by thorough experimentation.

*http://en.wikipedia.org/wiki/Wet_dreams