This is a bad way to teach a kid about animal anatomy. If you've ever seen the Jim Carrey movie 'Ace Ventura 2: When Nature Calls' you're probably reminded of the infamous rhino scene. Jim Carrey is playing spy in a big rhino suit, but when its gets too hot he needs to flee. There's only one way out, the butt. He climbs out of that rhino like he's getting birthed. It happens a lot slower than this slide would last.
The thing is that there's no way around this. You could flip the slide around and have the kids come out of the trunk, but then they'd be climbing right into his butt. Something tells me the slide would get a lot les use if that were the case. Except for that one weird kid who really likes to climb in. There's always a little weird kid who likes to do stuff like that.