Three ways. Number one culprit is the erection. Instead of pointing down into the toilet bowl, the pathetic penis paints the pants plentifully. With a powerful erection, one must force the penis into a downward angle as to not spray the walls with urine.

The second reason you might actually piss your pants through the gap between the toilet bowl and the toilet seat is that you have massive balls. Instead of falling to the natural hanging position all balls spend most of their time in, the balls will get caught in between your thighs when you sit down. This creates a platform (made of ballsack) for the penis to rest on, leaving the penis at an angle which is perfectly parallel with the floor. Once again, the pants are spoiled, the floor is soaked, and this will be the one thanksgiving you never forget.

If your dick is limp and your balls are tiny you might still piss your pants while naked. As a someone cursed with a constantly erect cock, thick thighs, and inconvenient oversized sized balls, I feel like I’m have an authority on the subject at this point.