Insertion of the thumb into the anus with the other hand raised above the head in an over-arching style such as an ape might perform when walking upright. The trousers and underwear should be at least at half-mast to allow the insertion of the opposing digit, or preferably you should be completely naked, to make it a classic Mogilla Gorilla. Use of the "oo-oo-oo" sound adds greatly to the effect.
The girls at the party were really prudish, so I dropped the Magilla Gorilla right through the middle of the lounge room. That livened things up!
by clemstar October 06, 2007
Usually a man, but sometimes a woman, who has a rocking hard body, but they're still to ugly to fuck.
Dude, I'm so drunk and horny I'd even fuck that Magilla Gorilla over there by the bar. As long as we don't kiss and it's doggy style.
by Mormon Jesus January 21, 2010