If you think about your mother, hopefully you can stop an erection in its tracks. If you've done enough Kegel exercises, you can woo yourself not to dribble. The mind is in the driver's seat, pumping out her own playlist.
But when it comes to goose-bumps, they join the likes of diarrhoea, yet another physiological hiccough you have no control over.
These pimply creatures creep up on you in the cold, when you read something wow, poignant, when you get a walk-over-the-grave connection with another world, when you become moved by Beethoven or the sound of your own voice. You probably won't pay attention, or you might get an ooh that's nice feeling, as you look down at the swarms of contracted hair follicles on your outer arm.
Last week in class, students were preparing a debate on Monarchy. They're French. They guillotined their royal assets yonks ago, so the republicans had it in the bag. I rolled my sleeves up and sat back in my plastic chair, ready for the quaint picture of crown-wearing to be picked apart and blasted with a sensible dose of democracy.
And then they played God Save the Queen.
The thing is, you don't protect yourself from such happenings. Emotions don't give you a warning beforehand that they're about to openly betray your body.
As the six bars of the anthem droned on, I rolled my sleeves down. What the hell was this? I looked about, checked that no-one had seen. Pierre might have, but he'd think it was because of the draught. He'd be hard pressed to imagine his teacher had been afflicted with goose-bump nationalism, surely.
As for me, I was horrified. Fearful too that I might start writing England for the English on walls and fill up my mantelpiece with Charles and Camilla memorabilia, get some of those little teaspoons with their little royal faces on.
Then one of the student's, Lucas, said one word. Like he'd gone and microscoped meaning. 'Belonging', he said. 'It's about belonging'. Despite the 'even ifs', he continued - even if they cost a fortune, even if they're a waste of land and chiffon sarees - ordinary people feel they belong to the great communal soap opera. And this became a valid argument in the eyes of these 20-year-old republicans.
And then it dawned on me. This was what my goose-bumps were about too.
With the God Save the Queen, I was being propelled back to the pub, to an England game, where I was urging the 11 men in white to win. Mud-slinging the enemy because it was fun. Perspective got clouded in the euphoria of the group and the free-flowing kegs of pale ale, and it was replaced by a togetherness, however momentary, which outshone any rational thinking. For 90 minutes plus half-time, I belonged.
And I'm not ok with that. I'm not ok with that at all.
Because the God Save the Queen moment brought out the pimples of the ex-pat. The most dangerous sort of human, who dips into nostalgia and makes a monument of it. The lost soul, far from home, getting goose-bumps for want of belonging.
Goosebumps elected Trump and a handful of other dictators. Goosebumps said Leave. Goosebumps hijack emotions and turn their owners into frothy-mouthed puppets.
So now my sleeves remain rolled down, buttoned up at the cuffs. I avoid large crowds, pubs, the Daily Mail and Trooping the Colour - in fact I stay at home most days - in a quest to defeat the unpredictable clutches of goose-bump nationalism.