When you haven't wacked off for a month and the cum has built up pressure, causing it to explode and drip off your hand.

When Larry from 1.0 is spotted walking in Burtonsville and someone makes a peepee on him.

Diarrhea/ Taking a dump or blasting liquid poop.

An Australian waterfall is the act of marinating a juicy t bone steak in a lady's period blood and proceeding to barbecue it.

when a female collects her period blood and pours it down a math book into her partner's mouth

When your fucking a person from behind and right before you cum you spin her around and cum in her nose then open her mouth and see the internal waterfall

An Italian Waterfall is where the man takes a piss into the woman's ass, then she proceeds to "waterfall" into the mans mouth.