Seeing as this thread has descended into the bowels (no pun intended) of decency, here's one for you.
A couple are walking along a country lane when she feels the call of nature. So she goes behind a hedge for a pee.
Her boyfriend, being a cheeky lad, decides this is a good opportunity for a 'feel', so he stretches his hand through the hedge and starts to grope. Suddenly, he comes across something large, hard and warm.
"Oh darling" he says, "have you changed sex?"
"No" she replies, "I've changed my mind - I'm having a crap..."