(to, used as a verb), this phrase is said to someone who is doing something meaningless, retarded and idiotic (not to mention potentially dangerous) and they are intelligent enough to know better.
a father comes home from work; his son is in his room shaving the hair off his own balls.
Father: son, you idiot, what are you doing? is this f-sag? i didn't tell you how to, or teach you, to shave your balls. Pigs don't fly.
Son: dad, this is not f-sag. yesterday after class, we went to her house and I had sex with my girlfriend Anna and when she gave me a blowjob and got to my balls, she complained how hairy they were. And yes dad, pigs do, and will, fly, if I deem it appropriate to attach balloons to them.
Father: so okay this is not f-sag, but roflmao anyways.
Father: son, you idiot, what are you doing? is this f-sag? i didn't tell you how to, or teach you, to shave your balls. Pigs don't fly.
Son: dad, this is not f-sag. yesterday after class, we went to her house and I had sex with my girlfriend Anna and when she gave me a blowjob and got to my balls, she complained how hairy they were. And yes dad, pigs do, and will, fly, if I deem it appropriate to attach balloons to them.
Father: so okay this is not f-sag, but roflmao anyways.
by Sexydimma May 5, 2012