I don’t remember it happening until I got older, but farting. Not generally, I’ve always farted and thoroughly enjoyed it, but since getting older I find I now fart involuntarily when under ‘duress’
The most obvious scenarios being
1/ on exercise of some sort – at boot camp in particular and doing abs work. Even worse is the knowledge it’s coming but you can’t stop it. We were doing one particular pairs exercise and on one repetition I managed to catch it just on a tiny squeaker….but I knew at the next rep immediately following; yep, whole class had to stop and nearly died from laughing as I made a sound like someone tearing a velvet curtain in half.
2/ As I’ve got older and weeing takes a bit more effort, it’s not unknown to rip one out at the same time as pushing for the last bit….. not so bad at home but in a pub, restaurant or works lavvie, is not an easy one to style out.