an anus that is riddled with fust,or a brown mossy type of fungus that is caused by lack of bum-hygene or clagnut infestations,mainly found surounding the clagnut riddled sphincters of fat girls,you can usually identify bumfust by the brown and black fluffy lumps of dryed shat and arse-hair,and also the ripe smell of arse vinegar and sour shit
i was just about to 69 the bitch when i got an eye full of bumfust!
her bumfust was of such a vast quantity that i puked on her beef curtains
by liam mccormack December 19, 2007
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