How does flushing water create air pressure? Are you using a steam toilet? Are you acoustic?

Did you just try to call me dumb when you don't understand physics?

Here's a little science experiment and explanation for you:

Water in a toilet bowl first rises as the flush begins before it over comes the pressure in the drain trap. Close the lid, more air is squeezed out the sides of the toilet for a moment as that happens, leave the lid up and you have a larger volume for the air to be offset in. Don't believe me, flush the toilet with the lid down, wet a finger with water slightly and put it near the opening between the lid and the bowl, you will feel it cool down from the air escaping. Do the same now with the lid open and you will notice this effect less. Obviously do this with a clean toilet and wash your hands afterwards but you will notice the pressure difference in the beginning.