One day, Pablo and Paco were riding their horses across the desert under the hot sun.

For a while, everything was quiet except for the sound of hooves in the sand.

Then Pablo suddenly smelled something awful.

He slowed his horse, turned around, and said, “Paco… did you soil your pants?”

Paco looked offended. “No, Pablo. I did not.”

Pablo nodded and kept riding.

A few minutes later, the smell became much worse. It was so bad that flies started buzzing around them.

Pablo stopped again, covered his nose, and looked back.

“Paco,” he said, “are you absolutely sure you did not soil your pants?”

Paco replied firmly, “Yes, Pablo. I am sure.”

So they continued.

But soon the smell became unbearable. Pablo was coughing, waving away flies, and nearly falling off his horse.

Finally, he jumped down, marched over to Paco, and said, “Get off your horse right now.”

Paco climbed down.

Pablo pointed at him and said, “Pull down your pants.”

Paco hesitated, then obeyed.

Pablo stared in horror and shouted, “Paco! I thought you said you did not soil your pants!”

Paco looked confused and replied:

“I thought you meant today.”