When you drop your pants and underwear then firmly grasping your dick and balls and pulling them up. Thus exposing your gooch. You also have the option to lean back or stand on your toes to give a better look to the recipient of the peek.
Man my teacher was a bitch the whole school year so on the last day before I walked out I gave her a Peek Under the Hood.
when a man's naked balls suddenly and unintentionally become visible, often through a space in his shorts.
Dave was speaking passionately against poverty in the third world, but no one could take him seriously cause the we were all snickering about his peek-a-balls.