What's the joke about the rough noodles of McDull Fish Ball?

Principal: Don't be rough.

McDull: Really? Laiwan fish ball rice noodles bar

Principal: No fish balls.

McDull: Really? Na tripe coarse noodles bar

Principal: Don't be rough.

McDull: Fish balls and noodles, then.

Principal: No fish balls.

Mcdull: Why is there nothing? Then let's eat squid balls and coarse noodles.

Principal: Don't be rough.

McDull: Sold out again? Bowl of fish balls and rice noodles, please.

Principal: No fish balls.

P: McDull, they are all sold out of fish balls and coarse noodles, but they are all gone.

Mcdull: Oh ~ ~! There is nothing in it ... please give me fish balls.

Principal: No fish balls.

McDull: What about the coarse flour?

Principal: Don't be rough.