Continuity mistake: At the end of the film as Joe and "family" are getting into the convertible, Christopher Walkens' character starts to get into the car and has one leg fully into the car, the next shot shows him still a few feet from the car and starting to lift his leg into the car.
Continuity mistake: When Joe Dirt meets the girl at the fair and is talking to her, in one shot her top straps are down, the very next shot she is pushing them down.
Continuity mistake: In the scene where Robbie is reading Joe the note from Brandy, Joe has dandruff on his shoulders. In another shot in the same scene, the dandruff is gone.
Continuity mistake: Seen from the hot air balloon, the passing airplane is a 747. In the close-ups of the cockpit, the plane is a Convair 880, as seen by the distinctive window arrangement.
Continuity mistake: The Indian's braids change length and density from his initial meeting with Joe to later scenes.
Continuity mistake: When Joe Dirt and the indian are in the desert and they are playing with the roman candles, Joe Dirt trips on the A-Bomb and the candle stick flies out of his hand. But in the next scene, when he wakes up the candle stick is in his hand again.
Continuity mistake: During Buffalo Bob's first appearance, he's holding a rake with both hands. In the next shot, he's holding it with just one hand.
Answer: It's not so much a joke with a punchline, but more like a funny phrase. He was affiliated with the mob, and as such, has most likely been in violent situations. He asks "does your mother sew" and then punches his refelection in the fire extinguisher case (someone's face if a fight was really happening). The "get her to sew that" comment implies that the person he hit would have needed stitches. (thus the reference to sewing.)
Jazetopher
He was referring to fixing the hole left in the clothes after being shot.