Warwick Avenue Share definition Flag (verb). Slang word used referring to when a one has anal intercourse. "You want to Warwick Avenue?" (boy 1) "Sure, meet me by the enterence of my tube"(boy 2). Warwick Avenue by scotty2hotty22 October 27, 2008 0 0 Get merch Get the Warwick Avenue mug. Buy Now — $32.95 See more merch