Are there any funny jokes about the Japanese?

A plane crashed on an island. Only one American, one China and one Japanese survived, but they met cannibals on the island. The patriarch told them that as long as the total length of DD of the three of you exceeds 20 cm, we won't eat you. The Americans first measured it, which was 12 cm long, and then it was from China, which was 7 cm long. The United States and China are loose. It's time to measure the Japanese. His length is exactly 2 cm, and the length of the three people adds up to more than 20 cm. Everyone breathed a sigh of relief ... after the cannibal left, the American said, "I am more than half of my length. Without me, you would have been finished." China people are unconvinced and say, Ya, my length is equal to the average. Without me, you would have finished. After a while, the Japanese broke out. If I didn't get an erection just now, you're all finished! !