Fender Tramp 

...A female who only dates Bikers. YOU MUST OWN A MOTORCYCLE OR SHE WILL NOT DATE YOU!

The phrase comes from bikers - it refers to where the passenger seat is mounted - on the back fender of the motorcycle, where most females ride.
Generally this is restricted to Harley-Davidsons, or custom choppers. However there are fender tramps who will date guys who own any brand of bike. Still a fender tramp, either way.

roaring motorcycle goes by ~~
..."bro there goes Lucy again, new boyfriend...

"dude shes a friggin fender tramp"...
...I know bro".

Fender Tramp by DJAK47NYC January 25, 2022

Fender Tramp 

A Fender Tramp is a female who only dates men that own motorcycles.

YOU MUST OWN A ROADWORTHY MOTORCYCLE OR SHE WILL NOT DATE YOU.
Cannot be a bike that won't start or junk in your garage - doesn't count.

...hey bro there goes Lucy again, she just slid onto a bare fender... off she goes!
...dude she's a straight up fender tramp. I'd never let her get on my chopper.
...hellz yeah.

Fender Tramp by DJAK47NYC January 25, 2022