An anus that has experienced more than a cock or two or three or four...at the same time. A "hector anus" is what happens after your asshole has been stretched by something the size of a basketball.
Patient: Doc, I can't tell if I am shitting or not! Poop just falls on the floor!
Doctor: Well, OMFG no wonder! Your asshole is the size of a hector! Your sphincter muscle has been damaged beyond repair! Prognosis not good, you have Hector Anus!