A Dutch Water Slide is when you get a lot of your friends to ejaculate on a large tarp and make hot girls go down it.
Me and my girls went to ride a Bob's Dutch Water Slide.
When you take your penis and stick it in a dump trucks exhaust pipe. When the dump trucks accelerates, smoke will start to flow inside your penis, giving you a temporary high.
"Did you hear what happened to Jim?"
"No, what happened?"
"He went weinerdumping and got a broken dick."