When an NFL wide receiver (but most notably Brandon Marshall, all 6-5 230 lbs. of him) steps on the face of or in general destroys the defensive back (or other defender) who is covering him after he catches the ball. And subsequently takes it into the endzone.
"Brandon Marshall is a defensive lineman playing wide receiver," Kansas City Chiefs cornerback Brandon Flowers said. "He wants to inflict punishment on you. He wants you to try to tackle him so he can shove you off of him and get more yards." So in short, Brandon Flowers has been Marshalled