It may or not be followed by the words "But I'm keeping high knees". In literal terms, this refers to the act of someone elevating their knees to avoid contact with the bitches who have tripped. In figurative terms, this refers to the act of someone trying to circumvent the problems the female is causing.
Jake: What man?
Mike: My mom took my phone away for a week, BBT, but I'm keeping high knees.
2. Jack: Dude why is your girlfriend making rumors about you?
Mark: I dunno man, BBT.