Breath restriction (Choking/Smothering)
Erotic asphyxiation forms, from using hands on the neck to pillow over face or sitting on someone’s face to restrict breathing. This can cause unconsciousness or worse if done wrong, so it’s edge play. Many people enjoy the headrush and submission aspect, but it should be done with immediate release at first sign of distress, and ideally not compress the airway fully (some safer choking involves sides of neck to slow blood flow slightly, but this is also very dangerous). Basically, don’t try this unless you accept the risks and have educated yourself.