Doodly-squat
Of no significance, rank or importance. The word “doodle” was in wide slang usage throughout the 19th Century to mean a fool, a clueless soldier or a penis. The term was in wide use during the Great Depression and was joined by the updated version "diddly-shit" in the 1960s.
“My gal is red hot (Your gal ain't doodly-squat)”
-- from the oft-covered 1950s song "Red Hot"
-- from the oft-covered 1950s song "Red Hot"
doodly-squat
The act (or attempt or result) of writing one's name in the snow by a female, or other such feat of aimed urination.
Courtney may be red hot, but you can't read her doodly-squat. Sue can doo it.