Among the 81 official sleep disorders listed in The International Classification of Sleep Disorders are a group of conditions called parasomnias. In this group, physical activity normally reserved for wakefulness sneaks out during sleep cycle transitions causing sufferers to walk, talk, even eat in their sleep. While it may look like they are consciously aware, they are completely oblivious to the action because they are technically asleep.
Some parasomnias however cause the afflicted to unknowingly act out their dreams or perform sexual acts. The problem can be so severe that people resort to restraining themselves at night to protect their loved ones.