A homosexual woman. (slander)
Man: "How did I know my girlfriend would run off with a clam bumper?"
by Spud January 27, 2004
"Gee, I never would've guessed that Rosie O'Donnell was a clam bumper.", he said sarcastically.
by Mike Stander August 01, 2003
One definition of lesbians, (clam meaning vagina) insisting that the two women have sex by rubbing one of their vaginas against the others vagina.
Cindy and Martha love eachother, they are probably clam bumpers.
by leanna :) April 07, 2006
Cassie Balleza from chowchilla that is really RANK. she smells like cottage cheese!!!!! shes a fat stupid bitch and often fucks sara merical, also a clam bumper who smokes oregano and thinks its bud!
Sarah and cassie fuck when they are together
by Cockmaster Bob January 12, 2004