It started because of some comic where a frog was taking a leak with his pants all the way down and someone questioned him about this. His response was...
"FEELS GOOD MAN"
Person 1: Why do you pull your pants all the way down to take a piss?
the opposite of feels good man. instead of waking up next to that beautiful woman you took home last night, you wake up in a stable with a sore ass. feels bad, man.