when you have sex and your intercourse partner cums on you're vaginal area and you forget to clean up and it dries up and stays on your vagina and it hardens into a crust
although the word seems to describe a crusty old vagina, it is actually a really cool nickname for someone with the name gina. Although they might not like it, its hilarious.
When a woman goes withoutshowering for a long period of time her vagine flaps develope a sort of crust that oderous. If this happens ladies, SHOWER IMMEDIETLY!