bass-ackward

Opposite or contrary to what is expected, completely disordered or disarranged, or that which is done incompetently. A euphemistic rearranging of "ass-backward," meaning the same. That's the last time I let you fix the electrical work by yourself. You've wired it all bass-ackward! I must not be completely awake yet, I just put my pants on bass-ackward!