I'VE NEVER found music exams to be particularly relaxing. During my first - as an adult, at least - I was overcome with such terrible shakes that I feared my saxophone would crash to the floor.

In my second, a fire alarm went off, the building was evacuated and we all stood for 40 minutes, shoving our chilly instruments up our jumpers in Sauchiehall Street. Why am I putting myself through this yet again? Trying to memorise the C# minor harmonic scale feels as natural to me as speaking Mandarin.

Sensing my stress, my teacher gives me a pamphlet entitled Developing Your Performance Routine. It suggests: "Arrange for your day to be as hassle-free as possible." I wake up, think, "eek, exam", and look out of the window. Snow is falling thickly, which means that the children might be sent home early from school. I picture every other child being taken home for hot soup and cosy fireside games - and my own kids, shivering in the school hall with the janitor because their mother is 28 miles away in Edinburgh.

Heck, I'll take them to the exam with me. They are mature enough to endure an hour's bus journey - and sit quietly in the exam venue's waiting room - without brawling or injuring themselves. The pamphlet suggests: "Before going on stage, most artists find it helpful to be alone to become mentally focused on their performance." All four of us are now crammed on the bus.

"I feel sick," bleats one of my sons behind me.

"You can't be sick on the bus," I hiss back. "Breathe deeply. Look out of the window."

A pause. I glance back; he looks horribly green. "Here," says a woman opposite, handing us a screwed-up paper hankie. "I've put cologne on it," she adds. "Get him to sniff it. It really helps with nausea."

I regard the tissue suspiciously but waft it under my son's nose anyway, thinking, what sort of example am I setting here, forcing him to inhale some unknown substance handed to us by a stranger? He squirms, tries to back away, and slams his hands over his mouth. "Gonna be sick," he splutters. I grab our posh string-handled paper carrier bag in which I'd brought the kids' packed lunches and tip the contents on to a vacant seat. My son vomits dramatically. I'll tell you something - paper carriers might look swish and be eco-friendly but they're not much cop as sick bags. It starts dripping out, all over my son's coat - a coat for which, incidentally, J paid £35 in John Lewis just a month ago. "There are often factors outside of your control," the pamphlet warned, "that can potentially interfere with performing."

The bus fills with a terrible stench, and there's a skiddy puddle on the floor. I couldn't care less about C# minor harmonic. "Arrive early for your performance," the pamphlet wittered - which I had planned to do, only now we have to stumble off the bus early in case my son throws up again.

I chuck his coat into a bin. Wasteful, certainly, but how could I possibly hope to impress an Associated Board examiner with a carrier bag at my feet, eking vomit? My son is now freezing. We lurch around Morningside's charity shops where I try to palm him off with a particularly vile tartan jacket in size seven-to-eight (he is 11). "I won't wear that," he complains. "It's matted."

I'll give him matted. My exam starts in 30 minutes and he's perusing the shop, not even the clothes section but books and games, as if we are on a leisurely shopping trip. Finally, he unearths a perfectly acceptable brown suede jacket that's only marginally too big. "What d'you think?" he asks, pulling it on.

"It looks great," I enthuse. He twists and turns, examining himself from every angle.

Tick. Tick. Exam starts in 15 minutes. The pamphlet's section on breathing exercises advised: "Feel tension draining out of the body through the soles of the feet and into the ground."

"I'm not sure." My son scowls into the mirror. "D'you think they have it in black?"

Contact Fiona at hello@fionagibson.com