They stole his clothes, thinking it would embarrass him. They did not count on him being so incredibly well hung.  Even soft, his huge cock stretched out the pouch of his jock. So, he wore that jock proudly, with no hint of embarrassment. The whole prank backfired. The pranksters ended up humiliated and embarrassed, seeing their girls checking out his meat.  Instantly they all knew that they failed to measure up and that he would get even with them, by boning their willing girlfriends.