"Nodding out" is a term that is used to describe the sensation of feeling suddenly very tired and nodding off or falling asleep. It is often associated with the use of drugs or alcohol, as these substances can cause drowsiness. However, it can also be caused by other factors, such as sleep deprivation or a medical condition. Nodding out can be dangerous, as it can lead to accidents or injury. It is important to be aware of the signs of nodding out and to seek help if you or someone you know is experiencing this symptom.