After having dirty butt sex, but before the dude cums, the dude says to his partner that he wishes to cum in there mouth. At which point he proceeds to the facial area of the partner and upon reaching said area he has explosive diarrhea poops all over his partner's face while cumming on his partner's chest.
Dude, last night i totally Window Washed some chick. I grabbed my clothes and ran out of the room before she realized that I diarrhea pooped all over her face. Nice!