To Munge (derivative of the italian term mangia, meaning eat) is to orally stimulate a female's vagina by "eating her out". Will usually result in an orgasm, and is often followed by a blowjob (if not done already) and or intercourse, as well as an increased willingness to make you sandwiches.
Bob: hey Fred, you having olga over tonight?
Fred: yeah man, gonna have a munge.
(verb) The act of ramming a live cactus up a woman's ass, and sloshing it back and forth, while gently and pleasurably fingering her pussy, until she simultaneously cums and bleeds, leaving her writhing in pleasure AND pain.
Guy 1: Dude, I got into a fight with my mom a few days ago, so as revenge, I munged the SHIT out of her last night.
Guy 2: Damn man, that's pretty harsh...
Guy 1: Yeah, I know, but it's to teach her a lesson!
When, upon finding a rotting, stank, bloated from sitting in the sun, and frankly just all around disgusting female corpse, one places one's mouth over the vaginal opening, punches the corpses stomach, and proceeds to devour any and all fluids that issue thereof.
Munging is the act in which one jumps on the stomach of a dead corpse and eating through fallatio the embalming fluids which erupt out of the corpse in the jumping process.