Choking game, also known as the fainting game

Dangerous game of trying to faint

The choking game (also known as the fainting game and a wide variety of slang terms) refers to intentionally cutting off oxygen to the brain with the goal of inducing temporary loss of consciousness and euphoria. The sequence of events leading to unconsciousness from hyperventilation is as follows[citation needed]:

Because the brain cannot store reserves of oxygen and, unlike other organs, has an exceedingly low tolerance of oxygen deprivation, it is highly vulnerable if vasoconstriction is not reversed. [11]

Any activity that deprives the brain of oxygen has the potential to cause moderate to severe brain cell death leading to permanent loss of neurological function ranging from difficulty in concentration or loss of short term memory capacity through severe, lifelong mental disability to death.

Source: en.wikipedia.org