Obviously means Bullshit Buddy, or a friend who is not a good friend but a moocher who forget you exist until they see something that they want from you.
Todd: Hold on man my phone's ringing
Jason: Who is it?
Todd: oh it just one of my BS buddies
Todd: Christan, i wonder what he wants now haven't talked to him in weeks, he's not gettin my stuff, damn moocher.