A very distinct type of individual who tends to sit far back on the toilet seat when shitting, often times leaving fecal crumbs on the back of the toilet seat. The SitBacker signature is characterized by a V shaped doo doo crumb pattern, produced by the combination of the squashing of ass cheeks on the toilet seat, and the ass crack.
Damn that SitBacker!! There's shit on the seat, and its the only stall open!!!FUUUCCCCKKKK!