when you hold back an impending crap long and hard enough that it actually creeps back upwards, buying you a little more time before either making it to a bathroom or shitting your pants
Carl suddenly had to take a shit on a floatplane but there was no bathroom, so he clenched up tight and forced an upturd.
Literally, it means you have turned over and looked beneath every possible stone. Idiomatically, it means you've looked everywhere you could and have done everything you could to try to solve some problem.
Dev: Didn't you find my book yet?
Ted: Believe me, I've left no stone unturned and did't find it.
An upturned collar, often called a "popped collar", is -- as the term obviously states -- a collar that has been upturned. It is best-known for its role during the 2000's as a part of "preppy" culture, something that many believe has worn out its welcome.
College Student 1: "My word, Lawrence, do you see that fellow student with the most audacious dress?"
College Student 2: "Egads! The youth with the upturned collar? Why, he must be visually impaired -- indeed, certainly! -- for he cannot see his current physical state; naturally, if he could, he would relieve his collar of its outdated duty posthaste!"
A fashion choice of rugby fans, usually associated with polo shirts, who spend most of there time in the toilet and very little time fixing there nose. The correct dress sense is also accompanied by the correct laddish body language such as; Mouth grabbing, arms behind head, or squeezing there faces!