a phrase used to mean "civilized" (however one defines this word) people don't behave the way you do. One can also add the adjective "normal" in front of the adjective civilized.
a boy, after having been to physical science class in elementary school and having learned the basics of electricity, tries putting scissors in the kitchen plug.

His mother starts screaming at him:

mother: is this f-sag you twit? what are you doing, you'll burn the damn house down. Pigs don't fly. Go to your room now. She then takes a broom and starts chasing him around the house.

son: I can attach balloons to anything i want, no? now please apply the phrase pigs don't fly to yourself. i haven't seen that many mothers chase their sons around their houses with bloody brooms; therefore this behavior, I will conclude, must be neither normal nor, in fact, civilized.
by Sexydimma August 20, 2012
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