Handled skilfully, the sleep-over is a useful rite of passage, writes Kathryn Holmquist

Sleeping over at my friend Suzy's house was an oasis in my teenage years. In my imagination, I can still walk in the lush and peaceful green of her family's "farm", still feel safe and cosy under the old American quilt on the brass bed, still see the Woodstock poster on Suzy's wall. I can still taste the chocolate-chip cookies, smell the horses in the barn and feel the splash of cold spring water on my skin on a scorching Southern day.

I know now that Suzy's family were no more saintly, accommodating or thrilling than my own or any other, but when you're a teenager, anybody's house - other than your own - is a paradise. A key factor in good mental health in teenagers is having an outlet other than your parents to turn to.

Wise parents encourage their children to form strong, emotionally sustaining relationships with people outside the family. It's only a strong parent who can bear to let their children go. And it's only a thoughtful parent who plans for this long before the teenager years arrive with all their complex baggage as they surf between being grown-up and being children.

Watch out - the parents who "enjoy" sleep-overs have cunning, long-term plans. They reckon that if they get their children's friends used to hanging out at their house, then this will continue through adolescence. As one mother of teenagers confided: "Some Sunday mornings I wake up and there are people I hardly even recognise sleeping on my sofa and everywhere else. But I don't mind, because at least I know what they're up to."

I think parents in this situation develop an unspoken pact. Parents get to know their children's friends and trust the parents of their children's friends to stand in their place.

Sleep-overs are important, bonding experiences, especially for little girls. I think boys enjoy them just as much, but the emotional intensity of a sleep-over seems to be more of a girl thing.

How many children should you have for a sleep-over? One friend is the easiest solution. They're more likely to fall asleep at a decent hour and less likely to fight. However, some children like to invite a gang over for a sleep-over, which has become a standard birthday party activity. Be warned - it isn't easy.

When I ran across a bleary-eyed friend in the local Spar one morning buying what looked like a hundred croissants, I knew that either she'd had a late-night party where everyone stayed, or she had subjected herself to the ultimate challenge of being the perfect parent - a birthday party sleep-over for six little girls. Having done this myself, I had every sympathy.

The girls arrive early in the evening full of excitement and good will.

For quite a while, they seem to entertain themselves and you think "piece of cake". But just around the time that you're serving the birthday cake, rifts may begin to emerge. Get any group of girls together and you're bound to have at least the chance of some emotional turmoil. They can't help it.

It's their programming. It's as though they're building up to an emotional peak and aren't happy until they've made someone cry.

This is where the parent comes in. Sleep-overs, I've learned from hard experience, require constant monitoring, not to mention diplomatic finesse.

The trick is to be involved without anyone noticing. The last thing your child wants is "Mom" putting a damper on things. Under the guise of delivering popcorn, making sure there are enough sleeping bags, checking the video is working properly, etc. You can listen out and use your emotional geigercounter to sense the shockwaves.

When the girls are getting tired and cranky, it's time to lay down the law: bed-time. With teenagers you can provide guidance, although you're more likely to hear them giggling hysterically until 4 a.m. than you are to hear them snoring. With younger children, you need to set a limit.

Realistically, you know there's no hope of having them asleep before midnight. To accomplish this, set bed-time at 10 p.m. It will take you two hours to settle everyone down. Once it is actually time to sleep, you have to sit in a chair in the room reading a book until they drift off. They will not do it by themselves. If you are not there to make sure they're really trying to sleep, they'll be up until 5 a.m. and no one will thank you - not the children, not their parents.

The children will be cranky for the rest of the weekend. And despite your best intentions, you'll find yourself awakening at least once during the night to quieten the giggles. Don't plan anything important for the Sunday following.

But don't get too uptight about it. Even if chaos ensues, at least you'll have the comfort of knowing that you've made your home welcoming to your child's friends and shown them a great time. Make home fun and your children will be less likely to seek entertainment on the streets. They'll have the confidence that comes with a home refuge where they can be "cool" with their friends. Parents of teenagers tell me this all the time, and I suspect they know what they're talking about.