The act of plowing your partner in the anal cavity while annointing him/her with oils & salts or holy water, as you recite passages from the Old and New Testament (specifically Mark 6:7, Acts 16:18, Mark 9:38-40). You then proceed to baptize the subjects face with your holy load in the "sign of the cross" and yell loudly "I HAVE EXERCISED THE DEMONS! This ass...is clear." Then you rip a page out of the Bible and tell them to wipe their face off with it and call them a dirty whore.
Your significant other uses the bathroom and afterwards you go in to find a horrible stench and that the walls are bleeding. You consult your local parish and they inform you that they are in dire need of an "Anal Exorcism".
"Dude her shit smelled so bad so I told I'd give her an anal excorsim!!"