Bathroom control

One day Pablo and Paco are riding through the desert on their horses. As they ride along, Pablo smells something horrible. He stops his horse and turns around. He says "Hey Paco, you shit your pants?" Paco says "No, Pablo, I did not shit my pants." He believes him and they keep riding. As they go on, the smell gets worse. The smell is so bad, flys begin to swarm. Pablo stops his horse and turns around. He then says "Paco, Are you sure you did not shit your pants?" Pablo says "Yes Pablo, I am sure I did not shit my pants." He says "Ok." They keep going and now the smell is getting to be unbearable. Pablo is swatting the flys away. Pablo stops his horse and gets of his horse. He then says "Paco, get of your horse. Paco, pull down your pants. Paco, I thought you said you did not shit your pants?" Paco replies "I thought you meant today!"