meth butt Share definition Flag A condition in which someone's ass constantly runs non-stop like the energy level of a meth addict. Or any overactive bowel condition. Dude, I tried to make it to the toilet but the meth butt just took over. I sharted everywhere. meth butt by Fendy21 October 23, 2008 0 0 Get merch Get the meth butt mug. Buy Now — $32.95 See more merch