When someone refers to a 'Blue Waffle' they're not referring to your typical blueberry breakfast-food.
A 'waffle' is a a slang term for vagina.
A 'blue waffle' is a slang term for a severe vaginal infection.
It's basically a slang term for an extremely nasty or severe vaginal infection/STD on the vagina. The infection could cause lesions on the outside of the vagina, as well as bruising, which causes it to look blue in color.
