hittin' porcelain 

A. When the penis rubs against the toilet while taking a shit. This is mostly caused by a poorly designed lid.

B. When a turd drops forcefully through the water, scraping the bottom of the toilet where it leaves a streak.

What's wrong with your toilet man? I was hittin' porcelain while takin a shit.

Did you hear that loud Thoomp? Well that was me hittin' porcelain in your freshly cleaned toilet.

hittin' porcelain by BoLiverwurst March 26, 2008

Hitting the porcelain. 

It is the act of hitting ceramic material with urine (usually the inside bowl of a toilet), so that you don't make any noise when you pee. More common amongst males than females for obvious reasons. It can be done whilst standing up or sitting down. It can also grow on you as you may start to see it as some sort of game.

Wife-"Honey, where were you?"
Husband-"Just using the restroom."
Wife-"How come I didn't notice this?"
Husband-"Well, I was hitting the porcelain."

Hitting the porcelain. by Orange Lizard December 6, 2010