Banana Alert Share definition Flag when a man wears trousers that are far too tight and you see the bulge of his penis in outrageous detail. Banana Alert!!! Look at Chris's trousers. What the fuck has he got down there? Banana Alert by Jellies99 June 19, 2015 0 0 Get merch Get the Banana Alert mug. Buy Now — $32.95 See more merch