Bitchrex Share definition Flag A dinosaur with PMT. Known to go on rampages. Also refers to anything which generally sucks or anyone who is being a tit. 1. Stop being such a bitchrex mannn" 2. Life's a bitchrex! Bitchrex by highland springs July 18, 2009 0 0 Get merch Get the Bitchrex mug. Buy Now — $32.95 See more merch