Courtesy of David R.
Rodney went to the zoo one day. While he was standing in front of the gorilla's enclosure, he noticed the gorilla watching him intently. Rodney waved at the gorilla, the gorilla waved back. He patted his stomach and the gorilla copied him. He jumped up and down, the gorilla started jumping. He made faces, pull his hair, hopped on one foot, spun in a circle, and beat on his chest. His antics were copied exactly by the gorilla in the cage.
All of a sudden the wind gusted and he got some grit in his eye. Rodney rubbed his eye, trying to make it better. While doing so he, he stepped closer and closer to the cage. As he pulled his eyelid down to dislodge the particle, the gorilla went crazy, banged against the bars, reached out, grabbed the nearly blinded man and beat Rodney senseless. When he came to, the zoo keeper was anxiously bending over him, and as soon as he was able to talk, he told the keeper what had happened. The zoo keeper nodded and explained, "In gorilla language, pulling down your eyelid means screw you".
The explanation didn't make the gorilla's victim feel any better but he accepted it. As he left, Rodney became madder and madder. He plotted his revenge. The next day he purchased two large knives, two party hats, two party horns, and a large sausage. Putting the sausage in his pants, he hurried to the zoo and over to the gorilla's cage, into which he tossed a hat, a knife, and a party horn.
Knowing that the big ape liked to mimic people, Rodney put on a party hat. The gorilla looked at him, and looked at the hat, and put it on. Next he picked up his horn and blew on it. The gorilla picked up his horn and did the same. He twirled in a circle blowing the horn. The gorilla did the same. Then Rodney picked up his knife and waved it over his head. Again the gorilla copied it. Next he whipped the sausage out of his pants, and sliced it neatly in two. The gorilla looked at the knife in his big hairy hand, looked at his own crotch, and pulled down his eyelid.