Now, whether the cold of the morning which was at hand, or whether some lenitive food on which he supped, or whether the motion was purely natural, which is rather to be believed, it so happened that Sancho had a desire to do what nobody could do for him. But so great was the fear that had possessed his heart, that he durst not stir the breadth of a finger from his master; and to think to leave that business undone, was also impossible: and so what he did for peace sake, was to let go his right hand which held the hinder part of the saddle, with which, softly, and without any noise, he loosed the running point that kept up his breeches; whereupon down they fell, and hung about his legs like shackles: then he lifted up his shirt the best he could, and exposed to the open air those parts which were none of the smallest. This being done, which he thought the best expedient towards getting out of that terrible anguish and distress, another and a greater difficulty attended him, which was, that he thought he could not ease himself without making some noise: so he set his teeth close, and squeezed up his shoulders, and held in his breath as much as possibly he could. But notwithstanding all these precautions, he was so unlucky after all as to make a little noise, very different from that which had put him into so great a fright. Don Quixote heard it, and said: "What noise is this, Sancho?"
--From Don Quixote de la Mancha--
All those poop jokes they have on TV? Just subtle homages to Don Quixote.