Acronym for 'better from behind'. Used to describe a visually challenged woman. Instead of adopting a missionary position or the girl on top, take the female from behind so one does not have to look at her face.
"Hey Nik, what was Angie like last night?"
"Oooh. A bit of a bfb, mate. We started off with her on top but Little Nikky was not not impressed - he retreated into his shell. Flipped her over and no probs. A lot better from behind."