Your boyfriend, Vino, was a biker and he loved taking you on his motorcycle. He called you his “backpack” The reference to a biker's "backpack" was well known among motorcycle riders. It was a term used to refer to their significant other, and the person who rode on the back of their bike. One day you were at a red light and a man (Brad) got out of his car and walked up to the motorcycle
He looks at you then at your boyfriend; his eyes scanned you up and down while a smirk formed on his face
Brad: “Damn, she yours?”
Vino: "She's my girlfriend, back the hell off"
The man's smirk turns into a cocky grin, clearly amused by your boyfriend's defensive response. He takes a step closer to the motorcycle, his eyes roaming over you once more before looking at Vino
Brad: "Damn, you're a lucky man. She's a pretty little thing, ain't she?"