A magnificent ancient ritual, the sacred union of cock and ass, celebrated "in the name of Priapus and in the spirit of cock", like the sexiest men in Roman antiquity did.
Jack made two mistakes. When he begins the ritual, his cock should have been hard and erect. No man can stand in the presence of Priapus with a flacid cock. When he gets on all fours and offers his ass ("In the spirit of cock"), he must take a cock in his mouth and then spread his ass cheeks.