A tatted-out, used-up lookin broad (sometimes a hottie) who rides on the back of a bike, smokes cigarettes, drinks wine coolers, tries to act tough, and has more balls than the insecure guy riding the bike. If she's a hottie, you wonder if she does trampish things. If she is not a hottie, you put that awful thought out of your mind.
"Hey Sam, you see that hot chick on the back of Snake's bike? No John, I don't, I see one big biker bitch ridin a sweet chrome horse, but wish she was ridin me.