Flump Buttocking Share definition Flag inserting a flump between two buttocks of a female during sex and the male eats it "Mann last nightt after we got the treats from Tesco's we were totaallyy flump buttocking each other" Flump Buttocking by Lily_kicks_ass_ October 23, 2007 0 0 Get merch Get the Flump Buttocking mug. Buy Now — $32.95 See more merch