Australian Waterslide

When a male ejaculates into the center of his partners back and has it slide down their partners back, down the butt-crack where it is then slurped up by yourself or a third person.

Dude you should have seen it Chad had Jason give his girl an Australian Waterslide at the Party last night.

Montreal waterslide

Ejaculating in a woman with her ass and the air and sliding the cum down between her cheeks with your dick.

I gave her a Montreal waterslide while she was leaning over the chair.