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