A prank played on someone whom passes out with their pants half-way down. A second person proceeds to slap a piece of white-american cheese on their ass-crack, then pull up their pants. The resulting heat melts the cheese and creates a philly cheese sandwich in their pants. The term "Hand Shake" coming from the motion of applying said cheese.
Jose` was passed out after drinking one night and being a dick to his wife. To get back at him, she slapped on a Philly Hand Shake. Yummy.