the low pitch echoing sound which is heard when one expels gas while sitting firmly on the toilet. Most commonly found when the air between blast of fecal matter is released while having diarrhea.
I walked into that bathroom and the dude in the last stall was playing the porcelain trumpet like a pro.
by 010101010101010101010101 April 27, 2011
by joshuah! September 28, 2006