A bloody ghost happens when you are going on a girl after you have already jizzed on her back, achieving superman status.
Then you pull out just before you
blow a load in her
bearded clam, and right after she turns around to give you a blowjob, you jizz on her face. Typically she is stunned, and that is when you punch her
in the face.
Thus, at last you have achieved the bloody ghost.