I have been on one if these rides they are super fun! If you are wondering if it hurts your back, the water park I went to had a board that would clip around you, so like having a small surfboard on your back. This was at Wet' n ' Wild in the Gold Coast in Queesland, Australia :)
Have you ever imagined if someone hammered a nail in from the outside of the slide and when you're sliding down, you see it but you can't stop because you're in a fucking slide and I'm sorry guys.
If so where?