A cousin pumper is a person who fucks their cousin. Typically these people originate from southern United States.
Bill: "dude did Brandon tell you about that chick Tia he banged last week?"
John: "Tia is his cousin, man..."
Bill: "gross that guy is a cousin pumper?!"
John: "Tia is his cousin, man..."
Bill: "gross that guy is a cousin pumper?!"
by Boobert Goobert September 27, 2017
Get the cousin pumpermug.