alabama backpack

When the smaller mate (regardless of sex (if female use stap-on similar to pegging)) rides on the back on the bigger one (who runs as fast as they can) while fucking them in the ass.

Guy 1: Yo last night my girl gave me the Alabama Backpack
Guy 2: Nice! How far did you run?

Guy 1: All the way to the gas station!

Guy2 : Damn!!