Someone of the Indy culture that carries a backpack everywhere they go for various artist/writing/ipod/iphone/other silliness. You can see them frequenting coffee houses and milling about universities.
When a straight girl gets fucked with a strap by a dyke that is kept in her backpack. And it’s so good it’s better than sex with a man for the first time.
I just had my firstbackpack experience. I am in love with her, but I have a boyfriend.
A girlfriend you carry around on your back.
Usually the girlfriend is smaller than you. She gets on your back and is transported that way. This allows for maxium closeness while traveling.