An extremely filthy version of sex. It starts when Person A begins to have a bowel movement. Just as the shit is about to exit the anus, Person B inserts his penis. Then Person B removes their penis and proceeds to shit into Person A's mouth. Then Person B inserts his shit-covered penis into Person A's mouth. After mixing up the shit, Person B removes his penis and inserts it back into Person A's anus.
In contrast to Sodomy, Gomorrahmy (to Gomorrahmize), refers to an even more unnatural act, namely, that of creating a completely new orifice, as by violence.
You are so hot...I just want to take a knife and Gomorrahmize you. I freaking love Gomorrahmy!!!