anything made by nike

The act of two women (lesbian or not) sitting across from each other with their legs spread open and sideways, allowing for full contact of their vagina to one another. Once in contact, they begin rubbing/grinding themselves against the other's vagina. Not entirely unlike the act of using a two-headed dildo and coming all the way together, only this does not involve a dildo.

A Ruthless fucking badass

Floatence is when somone over 500 pounds has so much methane gas causing them you fly up into the air and then make a very loud blarp noise.

When you really need to crap but there are no toilets near by so you pull out some paper and poop in that. Then you get carried away and start drawing rude things with your poop on that paper.

SIF means "Seat In Front."
It's a term used by unicycle riders to describe a way of doing a trick with the seat in front of you rather then the seat under your butt.