Mallrats!
One of the most underrated movies ever.
The whole joke, for those who missed this film is:
"One time my cousin Walter got this cat stuck in his ass. True story. He bought it at the local mall, so the whole fiasco wound up on the news. It was embarassing for my relatives and all. But the next week, he did it again. Different cat, same results, complete with a trip to the emergency room. Then, last week, I saw him in the pet store. He was buying another cat! I said, "Walt, what the hell are you doing, you know you're just gonna get this cat stuck up your bellybutton too, why don't you knock it off?" And he says to me, "Brodie, how the hell else am I supposed to get the gerbil out?" My cousin was a weird guy."