a down bitch
A down bitch is a girl who'll back you up no matter how bad things get. She'll ride with you through the fire, the flood, and the occasional jail cell.
She showed up to my probation hearing with a bag of chips and a death wish.
When I got fired, she took the job so I could keep my rent paid.
She drove me to the hospital after I got shot, and then she took my mom's meds for me.