The effect you get when you squeeze a tomato sauce
bottle and the sauce goes anywhere but at the food, usually
sideways onto your shirt or
pants. The effect can apply to any liquids including urine.
Example
1:
Person
1: "What happened to your shirt?"
Person 2: "Tomato Sauce Effect."
Person
1: "Oh right, yeah, I hate the Tomato Sauce Effect."
Example 2:
Person
1: "Hey man, why is there urine all around the toilet and on your pants?"
Person 2: "Sorry bro, I had a Tomato Sauce Effect."