Porcelain Tsunami is when your fucking someone in the bathroom from behind near the Toilet and you grab them by the neck or Head and put there head in the toilet and Flush it with there face in it before Busting a Nut.
The guttural and oft deafening resonance created when ass gas breaches the O-ring, slams into toilet water and bounces off the bowl. The resulting sound is both ghoulish and unholy.
My God! We better get the hell outta here. I was just in the Library bathroom and heard a porcelain ricochet that could only have come from a Yeti or a Nazgûl. Either way, I'm not sticking around to find out.