Have you ever done something that made you feel uncomfortable, just because someone you like told you to do it? Most of us have, and it can cause unpleasant feelings.

Mickey experienced those bad feelings when he stole a pack of his grandfather's cigarettes and smoked some of them with his friend John.

John and Mickey are in the same fifth-grade class in Washington. John is a popular boy, and Mickey really wants to be friends with him. So when John dared him to steal the cigarettes, Mickey didn't want to say no. "He may not like me any more if I say no," Mickey thought. So he did it, even though he knew it was wrong.

But when he and John smoked the cigarettes, Mickey felt awful. He suffered physically, because the cigarette smoke made him cough and feel like he was about to throw up. He also felt bad inside because he had stolen something from his grandfather, who trusts him. He also felt like he was letting himself down; he had made a vow that he would never smoke, because it can cause cancer and lung disease.

After that experience, Mickey wasn't so crazy about John any more. The next time John dared him to do something -- this time it was to steal some beer from the icebox in his house -- Mickey said, "No, I won't do that."

When he said "No," Mickey was surprised to find that John seemed to like him anyway. He even seemed kind of relieved. He just said, "Oh, O.K.," and the two boys went outside to shoot baskets in Mickey's driveway. The subject of the beer didn't come up again.

When John asked Mickey to do these things, he was using peer pressure. Your peers are people your own age -- your friends and your classmates. They are the people you see all day in class, and the ones you want to be popular and successful with. You want them to like you -- which is perfectly natural. So you may sometimes let them talk you into doing things that you know are wrong.

When you feel like you have to act a certain way or wear special clothes because they're cool, you're responding to peer pressure. If you insist on wearing pink high-top sneakers with all your clothes because everyone else in your class does, you aren't really hurting anything. But if you give in to peer pressure to do something like drink alcohol, steal, skip school or smoke, you could be heading for trouble.

Peer pressure to try alcohol can be very hard to resist, especially for kids. If you are in the fourth grade, you may already have been pressured to drink beer, wine or other alcohol to get "high." Experts say that one out of every seven fourth-graders in the United States has already gotten drunk. That's a lot of kids.

But remember -- for that one child, there are six others who knew how to say no.

Resisting peer pressure -- standing up for your own opinion, your own ideas, or your own way of doing things -- can be one of the most difficult things in the world. But it is possible.

It's easier to say no to something when you know why it's a bad idea to do it. Here are seven reasons why drinking alcohol is dumb -- one for every day of the week: :: It's bad for your body, especially during the years when you are growing fast. :: It makes you get drunk and act foolish. :: It makes you say things you don't mean or wish you hadn't said. :: It makes you do poorly in school. :: It gives you hangovers that make you feel sick the next day. :: It makes it hard to concentrate and do your homework. :: You can lose your good friends who don't drink.

If these reasons don't convince the person who wants you to try drinking, you can always say, "My mom and dad won't let me." Making your parents the "meanies" can be a good solution to resisting peer pressure sometimes.

There are many programs in schools and communities that are designed to help kids say no to alcohol and drugs. Among them are a network of "Just Say No" clubs all over the country. You or your parents can find out more by writing: Just Say No Clubs of America, 1777 N. California Blvd., Rm. 200, Walnut Creek, Calif. 94596. The National Institute on Alcohol Abuse and Alcoholism runs a "Be Smart, Don't Start" program in schools. For information, write to NIAAA, 5600 Fishers Lane, Rm. 13A54, Box BSDS, Rockville, Md. 20857.Tips for Parents

Parents of elementary school children may think "My child's too young to know about alcohol abuse." But they're wrong. According to the National Institute on Drug Abuse, American children are well aware of drug and alcohol use by the time they are in fourth grade; the American Academy of Pediatrics reports that one out of three fourth-graders believes that drinking is a "big problem" in their age group. Among fourth-graders, one in seven has consumed alcohol to the point of intoxication. In the U.S., 3 million children ages 14 to 17 are problem drinkers.

The American Academy of Pediatrics counsels parents who drink in moderation to be careful how the drug is used in the home. Having a drink should not be shown as a way to cope with problems. Don't drink in unsafe situations -- mowing the lawn, driving, using the stove. Never make light of getting drunk, and show your kids that there are ways to have fun without alcohol. Drinking does not always have to be a part of happy occasions or special events.

The National PTA plans a week of anti-alcohol activity, March 6-12, 1988. Contact the National PTA at 700 N. Rush St., Chicago, Ill., 60611-2571, or your local PTA for more information. A good book about communicating with kids about alcohol is "The Parent Connection: How to Talk to Your Child about Alcohol and Other Drugs" by Roberta Meyer (Franklin Watts; $14.95).

Catherine O'Neill is a free-lance writer in Baltimore.