A sex act involving one person laying one their back, lathering themselves in lubricant, after which another person performs a (usually large) jump onto the person covered in lubricant in an attempt to slide over the entirety of their body.
Tom: "Bro, did you hear that Sam flooberflopped Alex last week?"
Harry: "Yeah, he said it was like a slip n slide!"
When you have to pee in a movie but don’t want to miss anything, and must do the following mental equation: will the amount I have to pee cause enough discomfort to diminish my attention capacity for the remainder of the movie to an extent which is greater than the amount of the movie I would miss by making a mad dash to the restroom.
I saw Satantango last night, wonderful film but by the 5th hour I had to start doing pee calculus.