I’ve had it happen twice. Both times were an unfortunate combo of spicy food and exercise.
The first time I was on a 5 mile run, and the night before I had eaten a massive order of ghost pepper wings. Thought nothing of it as I felt fine when I woke up, but once I started climbing a hill my stomach started gurgling in a way I had never heard before. My whole body went ice cold at the same time that I started sweating. Cleared the hill, ran off the road into a ravine filled with scrub bush, ripped my pants down and just let it go. I can’t describe the sheer disgust and utter relief that accompanied it. There were some dewy maple leaves nearby which I used to clean myself as best I could and sort of... cover the mess.
Second and final time was the morning after I had annihilated some very spicy Indian buffet (lots of fiber in chick peas and lentils, I’ve learned). I was going extremely hard with abdominal crunches and suddenly my blood ran cold and my stomach gurgled. I made my way to the restroom, in a sort of panic stricken waddle, made it into the only private bathroom and let it go. I had to flush several times while still going just to make sure nothing clogged, but I made sure that there was no evidence once I was finished and thankfully there was an air freshening spray that I used copiously.
Lesson learned on my end- do not perform strenuous exercise the morning after spicy food and/or fibrous food. I won’t do any kind of exercise until I’ve had my, ah, morning movement and I keep extra spicy foods for midday meals now.