Short for Bong Rips. It originates from high people saying "Bong riiiiippppppppssss" to one another.
Often said in a high pitched voice and pronounced with a hard e, like creep. Used primarily as a call to fellow stoners to rally.
Guy 1: Brips, brips! Come and get your brips!
Guy 2: Brips, brips? Brips, brips!
Guy 1: Briiiipppsss indeed.