Millions of grown children are flocking home to visit Mom and Dad. They may be on break from college or completely self-supporting. Some are single or introducing new love interests. Others have spouses and tots in tow.

While it’s great to be back with family, self-sufficient adult offspring frequently digress to childish behavior when back under their parents’ roofs.

It’s easy to see why this happens. Adult children are in familiar surroundings, hanging out with siblings and friends. They recall when Mom did all their laundry or when snacks miraculously appeared the moment they got back from school. They easily kick into slovenly teenage habits, like dropping smelly tennis shoes in the middle of the kitchen, without thinking that someone else will have to pick them up.

At the same time, they resent their folks’ interference. When Dad adamantly refuses to let his daughter smoke a cigarette in his car, she issues a dramatic, “You-are-so-lame” sigh before finally putting it out.

Parents unwittingly contribute to the problem by treating the kids as if they were 12. Mom worries that her daughter looks tired. Dad launches into another lecture about how much money he’d saved by his son’s age.

They may also be reluctant to make grown kids pitch in and help. Folks tell themselves that the visit is a short one and that kids should enjoy themselves while they’re home. But deep down, resentment simmers. They could use extra hands during the holiday crush.

Adult children are equally frustrated. They’re happy to be visiting family. They don’t want to feel like they’re in fifth grade.

The answer, of course, resides with both parties. Returning kids need to remind themselves of their guest status. Mom and Dad live in the house year round. Adult children come and go as they please. At the same time, parents have the right to expect courtesy and cooperation. That way everyone can truly enjoy the visit.

HOW TO HANDLE THE GROWN KIDS’ HOMECOMING

TIPS FOR ADULT CHILDREN

• Respect your parents’ leadership. You’re in their home now. It’s time to follow their rules. Challenging their authority demotes you to the status of rebellious teenager — not a good place if you want to be treated like a grown up.

• Be tidy. Don’t let laundry pile up. Keep the bathroom clean. Never leave clutter for others to retrieve. Take good care of everything you brought.

• Offer to help. Check in regularly to see what you can do. Such chores as cooking, baby-sitting, doing dishes or running errands are in high demand this time of year. If you’re financially able, offer to buy groceries or take the family out to dinner. Your folks will probably refuse; the gesture speaks volumes about your character.

• Be sensitive to others’ schedules. Mom and Dad most likely keep different hours than you do. Honor their times for sleeping, exercising and eating. It’s the respectful thing to do. If you are up late or out visiting friends, be very careful not to disrupt the household.

• Be grateful. Say thanks for a home-cooked meal. Appreciate the house and love they provided while you were growing up. Ongoing gratitude demonstrates maturity and makes you a joy to be around.

TIPS FOR PARENTS

• Ask kids for help. Let adult children know what you need from them. They can’t always read your mind. You won’t be ruining their holiday. You’ll make them feel like an integral part of the clan.

• Don’t offer advice. The last thing adult children want is your opinion about their lifestyles. Keep your lips zipped unless they expressly ask for input.

• Express your approval. Kids never outgrow their need for parental praise. Let them know you adore them. Say, “I’m so proud of who you are.”

• Seek out pleasant topics and activities. Look for neutral, fun things to do with your grown kids. Make a fig pudding. Go wine tasting. See a movie. Take the grandkids to see Santa. Everyone will have a good time and look forward to coming again.

• Know that the visit will end. You love having family for Christmas. It always takes its toll. Enjoy the festivities while they’re happening. Then take a deep breath when they’re done.