The term that is used for someone willing to take the seat of a (usually) retarded person who calls "shotgun" in an attempt to obtain the front seat of a vehicle. However this must be said within a split second subsequently after the first person calls shotgun.
Person 1: "I call shotgun!"
Person 2: "Well I call double-pump shotgun, better get in the back of the van or it's gonna be one hell of a ride for you."
noun. An overly excessive and unnecessarily long nickname. It is often used purely for the sake of showing someone how "clever" you are. short form: B-chomp.
Dave: yo, whatup Sanj?
Sanj: whats happenin, B-chomp to the double pumpfakie?
Dave: you're an asshole