The year is 2222 and Mike and Maureen land on Mars after accumulating enough frequent flier miles. 

They meet a Martian couple and are talking about all sorts of things. Mike asks if Mars has a stock market, if they have laptop computers, how they make money, etc. 

Finally, Maureen brings up the subject of sex. "Just how do you guys do it?" asks Maureen. 

"Pretty much the way you do," responds the Martian. 

Discussion ensues and finally the couples decide to swap partners for the night and experience one another. 

Maureen and the male Martian go off to a bedroom where the Martian strips. 

He's got only a teeny, weeny member about half an inch long and just a quarter inch thick. 

I don't think this is going to work," says Maureen. 

"Why?" he asks, "What's the matter?" 

"Well," she replies, "It's just not long enough to reach me!" 

"No problem," he says, and proceeds to slap his forehead with his palm. With each slap of his forehead,  his member grows until it's quite impressively long.

"Well," she says, "That's quite impressive, but it's still pretty narrow...." 

"No problem," he says, and starts pulling his ears. With each pull, his member grows wider and wider until  the entire measurement is extremely exciting to the woman. 

"Wow!" she exclaims, as they fell into bed and made mad, passionate love. 

The next day the couples rejoin their normal partners and go their separate ways. 

As they walk along, Mike asks "Well, was it any good?" 

"I hate to say it," says Maureen, "but it was pretty wonderful. How about you?" 

"It was horrible," he replies, All I got was a headache. All she kept doing the whole time was slapping my forehead and pulling my ears."