1. Famous spell from the movie "Harry Potter & The Prisoner of Azakaban" which fends off Dementors with a white shield of positive energy when used by a young wizard.2. A sexual ritual, typically practiced by those with a fetish for Harry Potter or those who are simply a fan of humor, that occurs during the climax of sexual intercourse, in which the male pulls out of his partner, screams "Expecto Patronum", and ejaculates on him. Based on several scenes in the movie "Harry Potter & the Prisoner of Azkaban" in which young Potter fends off Dementors with a white shield of positive energy, where, symbollically, the male's penis represents a wand, the ejaculant represents the white shieldof positive energy, and the partner represents a dementor (Orginally conceived in Atlantic City on July 28th , 2006 in Pickles Deli/Restaurant)