In Peach Blossom Fan, Liu Jingting told a joke. I don't know what the answer means. Who can explain?

Magu Hotel: What's the story of the adherents in the early Qing Dynasty? Why not look at Manchu mythology? Is it a story about who Hou Fangyu went with? A needle without eyes and a needle tip is not a needle. A gourd that is not put into the water is not a gourd. It means a defective thing. What's worse, don't worry about its defects. On the other hand, it is not a criticism of the current disadvantages, but simply refers to the deer as a horse.