Guess the Orifice

A party game for a large group. Contestants are blindfolded and then stick their index finger through a hole in a wooden board. On the other side of the board is anything (preferably living) with an orifice. This can be human, animal, or anything with a distinct orifice. The winner must correctly identify the orifice source.
For even more excitement and great stakes, the winner gets to name one person who guessed incorrectly to clean the winners finger by using their mouth.