An expression signifying that you are in possession of some killer marijuana bud (kush, sour deisel etc.) on a Friday, and everything is going to be great because of that. Friday, generally being the end of the work week is a time to unwind and get ready for the weekend. What better way to unwind than with a big fat joint of some killer?
Guy #2: What up?
Guy #1: Pssh, killer on a Friday.
Guy #2: Oh word!?
Guy #1: Word son, lets twist one up and blaze on the way to the china buffet!
Guy #2: I fuckin' love killer on a Friday.
by Nipples Q. Johnson May 29, 2009
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