A couple has a male friend visiting from out-of-state, when an
 unexpected blizzard blows in, and keeps him from traveling.
  
 Since the couple has no guest room, he states his intention to
 find a nearby hotel, and be on his way in the morning.
  
 "Nonsense," says the wife. "Our bed is plenty big enough for all
 three of us, and we're all friends here."
  
 The husband concurs, and before long they're settled in: Husband
 in the middle, wife on his left, friend on his right.
  
 After a while, the husband begins snoring, and the wife sneaks
 over to the friend's side of the bed, and invites him to have sex
 with her. Naturally, he'd like to, but he's reluctant.
  
 "We're in the same bed with your husband!  He'll wake up, and
 he'll kill me."
  
 "Don't worry about him," she says, "he's such a sound sleeper,
 he'll never notice. If you don't believe me, just yank a hair out
 of his ass. He won't even wake up."
  
 So the friend does so, and sure enough, she's right. Her husband
 sleeps right through having a hair yanked out of his ass. So, she
 and the friend have sex, and then she goes back to her side of the
 bed.
  
 After about twenty minutes, though, she's back on his side of the
 bed, asking him to do it again. The same argument follows, another
 hair is yanked from the husband's ass, and again they have sex.
  
 This keeps up for about half the night, until after about the
 sixth time, when the wife goes back to her side. The husband rolls
 over, and whispers to his friend,
  
 "Listen, I don't care if you screw my wife, but could you please
 quit using my ass for a scoreboard?"