How about this one:
Holding in farts on an airplane and getting to the point where you have to slowly release the fart 2% - 5% at a time over a long span, and depending on how many people are within the radius of terror. But sometimes I question my judgment on the strength of the odor, and wonder if they can smell the small ones, and I'm just prolonging the suffering of the people around me by subjecting them to one fart every few minutes.
I had about 8 hours of contained airplane farts in me and I had to go back to the plane can just to sit on the toilet and fart.
It felt like there was a lung up ass.