Only expelling fecal matter in public restrooms when someone else is using the hand dryer, flushing the toilet, or anything that produces equal noise levels.
But...Hand dryers and toilets flushing only last for so long, therefore you must "spike it" to avoid making noise.
Commonly used by people who care too much about what other people think. Or those who wish to reduce unsavory bathroom noises.
Man there was alot of people in the crapper, I was spiking it hard!
Dude I the most brutal diarhhea, I didnt have the sphincter power to spike it, everyone heard and laughed.