bumb chum 

ur really gud friend (bum chum)

dem 2 galz r bumb chums

bumb chum by 2shae July 15, 2006

bumb chum 

Somebody you you share the area inside your ass with and they share theirs with you.

Both those fools gay, they must be bumb chums

bumb chum by Slick Mikey March 21, 2003