asleep at the switch

dead asleep

Sleeping in a deep sleep

fall asleep

To be affected by paresthesia; to go numb.

fast asleep

Sleeping, in a deep sleep.

sleeping at the switch

Alternative form of asleep at the switch.

sound asleep

Sleeping still and silently.

switch off

To lose interest, and start thinking about something else.

switch on

To change one's expression or appearance as if by turning a switch.