My Aunt Fanny

A way of politely calling bullshit when someone tries to give you an unbelievable excuse, line, lie, or over exaggeration.

The dog ate your homework? My Aunt Fanny!

by POP Gurl June 5, 2011

my great aunt fanny

fanny is a euphemism for the buttocks. So the exclamation "My Aunt Fanny!" or "My great Aunt Fanny!" is to say
"My ass!" as something of a perturbed rebuttal or reply

"I think YOU dented my car."

(surprise and denial) "My great Aunt Fanny! I did not!"

by theguywhobrokethebank November 2, 2013