My heart sinks at the idea of one of my children coming back home drunk (or God forbid I find them out and about drunk). It's a hard thing on any parent to have to deal with a teenager who made the unfortunate decision to take to alcohol. But keeping your cool about the ordeal is more likely to make a better impact than getting mad. So take a deep breath and follow a few of these steps.
Wait for them to sober up: Don't try to reason or lecture a drunk child. It just won't work. Put them to bed, give em' some hangover treatments the next morning, and let them sober up before the 'big talk'.
Ask them why they drank: First of all, ask them why they made the decision to drink. Listen to what they have to say. Don't judge. Often times peer pressure is involved- and that's a really hard thing for teens to overcome. Begin by always allowing your child to explain themselves.
Talk about why it's bad: Explain calmly why you don't approve of them drinking. How bad things could happen to them. Teen girls are more likely to be raped while drunk. Drinking and driving kills hundreds of people each day. Alcohol poisoning, although rare, DOES happen and is possible. And it's fair and simply against the law- so it's not okay.
Watch a DUI documentary: Typically my consequence for my child drinking, is to have them watch a teen-oriented documentary about DUI's. Most schools have these on hand, as well has MADD and SADD groups. Libraries also have them available. All will typically let you use them for free. If a child drinks in my house. The first thing we do is watch a video about the worst possible thing that often happens when drunk.
Attend an alcoholics anonymous group: My second consequence is to contact a local AA center, and ask them if my child and I can join one of their court-ordered groups (often filled with underage drinkers who were caught and arrested). We'll go through the entire session together- and attend an entire series worth of meetings.
If my child is adamant about drinking, I will create mature, monitored opportunities for them to drink in my home. This is a controversial topic that often goes un-discussed. I am open with social workers, therapists, and case workers about this. Not all of them approve, but most understand. If my child is drinking outside of the home- I feel as though it's better for them to drink with me. I, myself, never drink. But I'll allow certain kids to earn the ability to drink in my home. They can have a glass of wine or a bottle of beer on the weekends. They can experiment maturely. They'll be in a safe place where nothing bad can happen if they get intoxicated. They can learn to monitor their intake. And most of all they won't be drinking and driving. This rule largely depends on the age of the kid, their family history, and their maturity. But, I do feel that in cases where my child is drinking anyways- and I can't control their behavior, then I should at least be able to supervise their behavior.