You hear just the punchline in MIB, here's the full joke:
So a man and a woman decided to take in a movie one night, and it just so happens that on that same night a farmer has decided to sneak in one of his roosters (or c0cks) from his farm.
After getting their snacks the couple head into the darkened auditorium, which is nearly full there are only two seats left, and they happen to be next to the farmer and the rooster which he has concealed in his pants.
Midway through the movie he rooster pokes his head out of the farmer's zipper and begins to peck and eat the woman's popcorn, she notices and nudges her husband;
"Honey, look what this guy's c0ck is doing!"
Her husband replies; "Ah, don't pay it no mind, if you've seen one you've seen 'em all!"
So she looks over at her husband and says; " Yeah, but Honey this one's eating my popcorn!'