When you take a sip of someone's water without touching it with your mouth.
Ex. Hey can I waterfall, I finished my bottle.
Ex 2. I need a waterfall I'm dying of thirst.
I don't care what you say, in New Jersey WE DONT SAY AIRSIP omg we say waterfall you can't be my friend if you say 'airsip' like bro its a waterfall.
Hey bro can I have a waterfall?
It is a way of releasing toxins from your body via shitting such loose materials, known as diarrhea, at such a force it is like a waterfall
Wow, that health shot at whole foods had me waterfalling!
When your girl cums and she asks you to drink it up
Girl: oh my! I'm going to cum!
Boy: U aren't gunna make me waterfall again are you?
Girl: u bet I am
Getting a girl so wet that it dripping
girl one: bihhh he gave me waterfalls i stg
girl two: ugh i love that shi
A built-in waterfall is a slang term for a well-lubricated vagina. One that is very wet and moist. One that has been aroused and may be expecting company.
Her built-in waterfall was inviting