In med school, a family medicine attending told the following joke in a lecture to our entire class in physical diagnosis:
A city-slicker wanted some time away from the hustle and bustle of city life. He signed on to herd sheep for a summer. The previous shepherd is teaching him the ropes and mentions, and if you ever get bored, just have your way with the sheep, we all do it. The city-slicker is disgusted, but as the months go by, he becomes rather lonely and decides to give it a try.
The summer ends and he is giving report to the shepherd whose advice he had taken. He informs the shepherd that he gave it a try and wasnt that bad. The shepherd asks him which sheep he had used, and he points to the victim, at which time, the shepherd falls on the ground in peels of laughter.
The city-slicker is mortified, fearing that the shepherd would spread the tale of the sheep-loving city-slicker far and wide. He asks, So, you havent ever fornicated with a sheep before I take it? The shepherd, hardly able to talk through his laughter stutters
You picked the ugliest one!
Come to think of it, I think my attending was from Texas. Maybe it was a autobiographical joke?