jiz waterfall Share definition Flag (noun) the ooze of jiz that emerges from a vagina around 11am the morning after it was deposited there. Aww, man! I need to go change my underwear. I just had a jiz waterfall. jiz waterfall by jiz can March 18, 2011 0 0 Get merch Get the jiz waterfall mug. Buy Now — $32.95 See more merch