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1.
Cancer of the bum. Otherwise known as Colon cancer, or in general cases, any bum related injury. Piercing a bum cancer tumour can lead to potentially fatal bum AIDS.
Katie: I think I have bum cancer. My ass is bleeding.
Me: You do not have the bum cancer, you ass.

Katie: I hurt my ass:(
Me: What's that I hear? BUM CANCER?! You have bum cancer?! Ergh.
by Kirstylovesthebum January 12, 2008