A homosexual woman. (slander)
Man: "How did I know my girlfriend would run off with a clam bumper?"
de Spud 27 janvier 2004
"Gee, I never would've guessed that Rosie O'Donnell was a clam bumper.", he said sarcastically.
de Mike Stander 1 août 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.
de leanna :) 7 avril 2006