The result of a crappy band name maker, Penis Avalanche is the name of the dopest jazz band in the northern hemisphere. Playing hit singles such as "Trunk of the Pussy Spray" and "Fuck Mel Gibson" the band has quickly gained success as the number one band in Albion, Washington.
The band has since broken up, and reformed so often, that most of the members have no longer play an instrument and instead stare awkwardly at each other for the better part of 12 hours while watching hipster music videos on Youtube and making fun of their poor bass player.
When a man stands behind a bald person on their knees and slowly cums on the top of their head so it will run down the persons face, like an avalanche runs down a mountain.
First defined in NASIOC's Off Topic forum by Kaiser as the slow, crampy, painful, and excruciatingly long build-up of poo in one's bowels, which finally reaches a breaking point and results in a massive avalanche of crap being explosively expelled from one's ass. Hence, assalanche.
Zeke sat miserably on the toilet for 30 mins with bad stomach cramps -- a half hour cycle of cramping and loosening and cramping and loosening tearing at his abdomen. But, frustratingly, no poo was shat. He suffered wave after wave of pain...until, finally, that last little snowflake fluttered down on 500 billion tons of brown snow. The assalanche came without warning, and it was fierce. Many people in Toiletville were caught unaware and perished in a 100mph rush of furious poo.