The phrase had been used a year earlier, in an article on "The Year 2000" by Joseph Goebbels:
"If the German people lay down their weapons, the Soviets, according to the agreement between Roosevelt, Churchill and Stalin, would occupy all of East and Southeast Europe along with the greater part of the Reich. An iron curtain would fall over this enormous territory controlled by the Soviet Union, behind which nations would be slaughtered."
Note that Schrödinger's panties refers to the improbable situation while iron curtain refers to the skirt.
Is the secret behind iron curtain superglue?
Person 2: "At least you didn't get bunned"