When a woman's labias hang out or pertrude out to resemble two pieces of folded lunch meat. Some vaginas are this way naturally, though they tend to get that way from a lot of usage like with pornstars or a ho.
"Damn that bitche's pussy's been so beat up she's got lunch meat pussy."
"I got some man-naise to go with that lunch meat pussy!"
Pussy munch is where you get your vagina and you put food in it - Then you move the flaps as if they were lips. The food gets crushed and your partner is then able to gobble on it - or you could eat it yourself ;)
Have fun doing the pussymunch.