One day ... I was riding maybe a bit too fast and had eaten maybe a bit too much and so I wasn't feeling very well in my stomach.
Suddenly, a fly flew in my mouth just I (mistakenly) inhaled through my mouth and somehow, because of the shock, I ended up swallowing it.
I stopped and started to vommit while still lurched over my bike.

Since then ... I never inhale through my mouth anymore.