A big fat turd that exits out one's ass in the shape of a giant log possibly resembling a large seqoia tree floating in your toilet.

the word bum refers to the ass; the log refers to the turd.
Tara is such a Schlob she backed up the sewer system with her giant bum logs
by jayfred June 6, 2004
A huge turd basically...Yeno one that clogs the bog.
In fact so big, that you would of thought it was a child.
Tim: Damn ! I need a Shit !
Tom: Go for one then.
Callum: Yeah dude you better not shit in my room, knowing you, you've probably had Indian food or Cat food or something like that ?!
Tim: Fine! But i reckon its gonna be a bum log cos my ring is well stinging !
by The Mighty Turd ! May 15, 2010