It's going to happen, however, and if you're lucky, it will happen while you're still young. I mean, it's obviously going to happen a lot when you're first starting out in life. That doesn't count. I'm saying it should happen at a point in your development when you understand what kind of crisis you're facing. You certainly don't want to shit your pants for the first time ever as an adult, right? You should have already choreographed your routine for dealing with that calamity by that point in life.
Just follow along.
For me, the first really vivid memory I have of shitting my pants happened when I was maybe 9 years old. I was about as good at making friends back then as I am now and, as such, had walked to a nearby church to throw a ball against a wall. So, I was basically playing catch with a building when I had that undeniable rumble in my stomach and knew disaster was imminent. It was. So imminent. I don't recall what I had for breakfast that morning or for dinner the night before -- I just knew my body wanted something out of me, and it wasn't going to wait for me to throw an imaginary perfect game against a house of worship to make it happen.
The span of time between me realizing what was going to happen and that awful thing actually happening was unspeakably slim, to the point that I didn't really have time to plan. I only had time to react when it was over. And that's the important part! That's the thing you don't want to have to sort out as an adult. Go into your responsibility-filled years confident that you know exactly what to do if you shart (or worse) while out in the wild.
Stare back at them.
I had a friend who shit his pants on the first day of school in sixth grade, but managed to make it through the entire rest of the year without being known as "that kid who had the power runs on the first day." Why? Because he handled the situation without making a spectacle of himself. That's what winners do. In fact, if my quick Googling of his super-common name in conjunction with the state I grew up in are any indication, that guy runs a bank now.
I also handled my introduction to public explosions pretty well. The first order of business, as it should obviously always be, was to find the nearest bathroom. For me, that meant an Apollo gas station six blocks away. From there, as should be the case for anyone, animal instinct took over. That's the part of a pants-shitting story you don't tell -- the gritty details about the cleanup. You're stewing in your own filth. Get that filth off in whatever way you need to, and dispose of the evidence, even if it's just long enough to flee the scene without anyone getting a good enough look at your face to form an accurate description.