Shazoop is a combination of Shazam, and Shoop. Shazam, by definition, is "Exclamatory phrase used when striking an unsuspecting victim in the genitalia with a foreign apparatus such as a back scratcher or a crow bar.". Combined with the power of the shoop ("to put something sweaty on hand, then sneak up behind someone and wipe your hand in their mouth"), you get the even more mighty Shazoop.
Hey Josh! I shazooped Jessie so bad! I hit him in the sac with a lamp and then put my ball sweat all over his mouth.