Sexsomnia is the term for a sleep disorder which, like sleepwalking, belongs to the area of parasomnias and to the group of non-organic sleep disorders. This disorder is a state in which the affected person is apparently awake, performs sexual acts such as masturbation or, in the presence of another person, sexual intercourse, but does not come to consciousness from non-REM sleep and often cannot remember his or her actions after waking up.
Source: tatoeba (8308184)