kidney butt Share definition Flag The overflowing fat pushed up and out of one's way too tight jeans, which causes the said fat to be repositioned at kidney level. Hey bro..... That chick is smokin hot, but check out her kidney butt!!! kidney butt by gnrcoax762 May 14, 2012 0 0 Get merch Get the kidney butt mug. Buy Now — $32.95 See more merch