The first time I remember it happening was in P6. We had been asked, as part of a history topic, to draw George Wishart preaching. The boy next to me had many talents but the rendition of likenesses of early Proddies was not one of them. A head cribbed from "The Scream" was topped with a bird's nest. It sat upon a scarecrow torso that sprouted asymmetric limbs, one arm growing from the waist, the other from slightly below the shoulder.
As the rest of the class worked silently, the boy and I looked at one another, then to his drawing. As we caught each other's eyes again, the laughter started up, suppressed at first with ease but with increasing difficulty as each attempt to uncross George Wishart's eyes or equalise the lengths of his legs only made the image more hilarious. Keeping it in was like trying to hide a revved up two-stroke chainsaw under a T-shirt. Soon the reprimands came, good-natured at first but increasingly laden with irritation as the sniggering and snorting continued to burst forth.
At secondary the affliction resurfaced several times, even during my Higher biology exam when a friend entered the hall sporting the first Alan Rough perm in Lanark. I am not alone. The head of department claimed to have been thrown out of a mountaineering lecture. The speaker was showing slides of his Himalayan trip, one of which featured Sherpas carrying supplies in old tea chests. "What do they want all that tea for?" the PT asked his mate. With the help of a previous pint or four, they succumbed to the giggles and were asked to leave.
I, too, failed to grow out of ill-controlled laughing. At university we had a rather poor maths lecturer who resembled the space alien at the end of Star Trek's closing credits, the one with the shock of vertical white hair. He was habitually clothed in an elongated Columbo-style mac and trousers that, due to their inequality of leg length, would have been ideal for my primary pal's George Wishart. His appearance should not have been enough to induce mirth in fairly politically correct students who were no oil paintings themselves. Unfortunately, the lecturer had a couple of bizarre blackboard habits to help things along. Having scrawled several lines of a differential equation on the board, he would stand back, arms folded, with his lower jaw thrust forwards like the open drawer of a cash register. Worse was his practice of eschewing any mechanism for raising a blackboard frame in favour of doing the splits as he worked his way down. I still remember almost having to dive out of a tutorial room when he performed both actions simultaneously.
As a result of these experiences, I vowed at teacher training college that, should I come across a pupil in agony suppressing a fit of giggles, I would make some light remark to allow him or her to laugh out loud and be done with it. And I kept my vow, right up until the time a girl actually did have a fit of ill-suppressed giggles. I told her to behave herself or I would put her out until she settled down. Hypocritical? Don't make me laugh.
Gregor Steele has a recurrent nightmare where he has to apologise for laughing uncontrollably at a staff assembly.