Similar to the athletic competition phenomenon (home field advantage), it is believed that your home toilet bowl has an advantage over all others, in that your ass is more familiar with the resting spot ultimately resulting in a far more comfortable and superior performing shit.

Taking a dump in your own bathroom.

When having a party and inviting your girl over to score, you have an advantage of taking her to your room during and after the party.

When a person only feels comfortable defecating when they are in their own home.
(Note-Similar to Home Ground Advantage)

When you wake up "the morning after", having hooked up at your own place, and THEY get to do the walk of shame. Not you.

an excuse for Jackson Merryman to say that he is better than his friends at Nidhogg.
Really he is a bitch ass and can't win a fucking game against the master Simon.

To have an advantage in a sporting event with your home fans, city, state, etc. Visiting teams have a higher chance of losing because the home team has more support of winning.