The act of "tucking" in ones penis and balls between his legs, to simulate the image of a vagina. The character "Buffalo Bill" does this in the movie Silence of the Lambs and dances to Q Lazarus's Goodbye horses. The typical "mangina" can be found in scenes also from such movies as, The Clerks and Scary Movie 2.
A word used for a gay man's pooper. Gay men don't have vaginas for a penis to be inserted into. As such, they deam their butt plugging poopers to be there "mangina".
Kevin screamed and moaned as his mangina got pounded by his well hungboyfriend!