R IS for restraint and boy, will you need it. If you thought dealing with a two-year-old was bad, wait until that two-year-old is towering above you awash with hormones, sulkiness, stubble and a disdainfully curled lip.

I love my boys dearly, would kill anyone who harmed a hair on their heads. Yet at times, I would have cheerfully knocked them into the middle of next week, banged their heads against a wall or given them away to any passing slave trader. Sound familiar?

Take comfort, you are not alone.

It would be good to say that it was my innate restraint and common sense which prevented me, but actually it was the simple fact that they were bigger than I was.

Have you noticed that all these anti-smacking campaigners always go on about how it is morally wrong to hit a child? There's a much better reason not to - if you get into the habit of hitting a small child, then watch out. One day he will be bigger than you with muscles like Popeye's and will hit you back. So far better not to give him ideas in the first place. Nothing to do with moral courage and all to do with self-preservation and cowardice.

Teenagers are deliberately designed to drive you up the wall. It is Nature's way of making it easier for the parting of the ways. Effective, isn't it?

But as you have to rub along together at least until they are 18 or so, restraint also means keeping your lip buttoned occasionally about their clothes, friends, music, spots...

Faced with an angry outburst of teenage acne, it is neither kind nor clever, however tempting, to go round the house singing "Spotty Muldoon", and it is probably a lot more cruel than trying to hit them.

No, just stock the bathroom cabinet with Clearasil and say not a word.

If you can't stand their friends, especially their girlfriends, then keep ultra quiet. Your loudly-voiced disapproval is a sure and certain way of cementing a dodgy friendship. They'll learn.

Restraint means that you cannot run their lives for them. You can hint, guide, suggest, even occasionally nag, but sometimes they have to make their own mistakes and work things out for themselves, however misguidedly and muddle-headedly. You nagging them to bits, sadly, isn't going to help much.

When Senior Son first went off to university, we all knew it was a mistake. It was the wrong course at the wrong time and he was still only 17. "Are you sure about this?" asked his teachers.

"Have a gap year," we suggested. "Think again," we pleaded. "Just wait a year," we tried.

But no, he said scornfully, it was his life, he was sure he knew what he was doing, and in the end we had to let him get on with it.

Which is why, a term and a half - and a lot of money - later, he was sitting in front of me looking utterly miserable. He'd chosen the wrong course, he said. Wasn't happy, we knew. Wanted to drop out, he thought. All in all, he said, as if this wonderfully original idea had only just occurred to him, it might have been better if he'd had a gap year.

At which point, I forgot all about restraint.

"I cannot resist this," I said with glorious lack of self-control, "but I told you so!"

After 18 years of trying to keep my lip buttoned, I thought it was the least I deserved.