Slumped on a suburban train one Saturday morning, I ran into a girls' nite out. Ten heavily made-up and scantily clad girls were announcing their plans to the carriage: loadsa drinks at a riverside pub, pizza, then loadsa drinks, Chinese to mop up the alcohol, then on to a night club; loadsa . . . well, who knows? They didn't expect to be crawling home till about two the next morning.

When a group of stocky lads climbed on, heading for a Chelsea football match, they were quickly seen off by the ladettes, whose innuendo and wit was more than a match for them. The girls were off to have a good time, and no one was going to get in their way.

My own nights out with the girls are altogether less raucous occasions. Sometimes it's a group of former Newsnight producers agonising about having it all, or at least juggling it all. Sometimes it's local mums arguing about the merits of our kids' teachers over rioja and pasta. But there's something about a night out with the girls that makes the occasion special: a set of shared assumptions, tribal bonding - call it what you will, it's fun. The lads have known this since time began. So what makes a good nite out with the girls?

First, drink a lot, mix your drinks. Ignore the old adage about grape and grain: start with some lagers, move on to wine, finally a cocktail or two. Then, throw discretion to the wind: these are girls you can trust - or they should be. So divulge your latest worry about your daughter's aggression, your boyfriend or spouse's intimate habits, your own unwelcome aches and pimples - with luck, everyone will be too drunk to remember in the morning. But, most of all, have a laugh. What is the point of these single-sex evenings if not to have a few rollicking good jokes about the opposite sex and all their (many) shortcomings? Hell, you can be sure that's what the boys are doing.