The Dirty Gandalf is the art of masturbating on to the Chin of your partner, creating a messy white beard of spooge, they must then shout "You shall not pass!". To add extra credibility to the act, midgets dressed as Hobbits may be used as well as other props like robes, staff etc. Photographs must me taken for posterity.
Darling , I have ordered midgets for tonight, get your robe on, its time for Dirty Gandalf to arrive.
When a lad requires the assistance and guidance of a lass in order to pull some fit piece of ass, the lass in question is providing the role of vaginal gandalf
A unique kind of orgasm only available to LSD users and Lord of the Rings fans.
When you ejaculate, the semen morphs into a small wizard statuette, then starts glowing, and a voice is heared yelling the words: "YOU SHALL NOT PASS".
A female version of this has not yet been discovered.