The term “bj” stands for “bad joint”. you will use this phrase when referring to absolutelyanything at all, and you can use it very loosely, but is typically used to refer to a place or object. You can use this slang as either bj or bad joint.
"Man, I done did a bj today, I was 'posed to polish off that table with the 100 grit sandpaper, right, and I went with the 69 instead, my boss won't like that shit one bit, cuh, I'm finished."