Basically the guacamole machine is when a guy is eating out a girl with a really long clitoris (usually like 5-6 inches long) and lots of feces get clogged up inside her vagina. So while he's eating her out lots of green shit comes out. Usually it's the remains from her menstruation or eggs being "broken" or not taking showers. The taste is that of rotten fish or smelly ass onions that have rotten for months.
Gabby or other shitty girls who don't keep themselves clean in any way and therefore have a guacamole machine.
by N4Sir August 12, 2009