One day, a space ship landed in a farmer's field and a Martian man and his wife got out and introduced themselves to the farmer and his wife.
As a token of his friendship, the farmer immediately invited the Martian couple in his home and begged them to stay for the evening and have dinner, so the Martians agreed.
Later that night, the Martian man explained how, on their planet, it was customary to swap partners as a token of friendship.
The farmer, not wanting to offend his alien neighbors, readily agreed. The Martian man then took the farmer's wife into one bedroom while the farmer took the Martian woman into another.
They had been having sex for about an hour when the Martian man asked the farmer's wife, "Well, how do you like having sex with a Martian? How does it feel?"
The farmer's wife replied "It needs to be a little bigger around." So the Martian man twisted his right ear and presto, his penis became bigger around.
About an hour later, the Martian man asked the farmer's wife again "How does it feel now?" The farmer's wife responded "I think it needs to be a little longer."
So the Martian man twisted his left ear and presto, his penis became longer.
The next morning, after their alien neighbors had left, the farmer and his wife were having coffee at the breakfast table and the farmer asked his wife "How was the Martian man?"
To this, the farmer's wife replied "Fine." "And how about the Martian woman?"
The farmer replied, "That damn b*tch yanked on my f*cking ears all night long!"