Binge drinking is consuming a large quantity of alcohol in a short period of time.
Simple guideline: when a female has 4 drinks in a 2-hour period or when a male has 5 drinks in a 2-hour period.
Drinking under the age of 21 is illegal.
Underage folks are encouraged to make the call in a life-threatening emergency even if they have been consuming alcohol and/or drugs. Many jurisdictions provide limited legal immunity for underage persons involved.