Lenny Bruce used to do this routine about a man who gets discovered by his wife in bed with a chicken (apparently theres a law against sex with a chicken in New York State).

the wife says, how could you....with a chicken!
the man says, okay I was in bed with the chicken, but all the time its YOU I was thinking of........

You know that's one sexual tabu, I've never heard a folk song about. all these pretty ploughboys ...its funny I bet there was alot of it going on, but they kept quiet about it. all except the pheasant plucker's son.