A fart released when shitting or just sitting on a toilet, that emits a thunderous sound, usually staccato, due in part to the natural spreading of the arse cheeks when enthroned.

A skilled funnel trumpeter can control a sustained funnel trumpet note by using sphincter control and circular anal breathing techniques.
The bloke in the cubicle next to me was blasting the funnel trumpet a moment ago, I could barely contain my laughter.
by Peado Bear December 2, 2010
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