The book, “642 Things to Write About” has writing prompts to get those creative juices flowing such as:
Write a sex scene you wouldn’t show your mom. Describe a time when you wanted to orgasm but couldn’t. Write an X-rated Disney scenario. Write a scene that begins: ‘It was the first time I killed a man.’ You are a serial killer. What TV shows are on your DVR list? Why?
Apparently the book was part of a college level writing course that was being taught at the high school.
I dunno if giving students a workbook which has sexual content qualifies as "child pornography", but those do seem rather inappropriate. Unless you want your kid to start their porn writing career off early and right. Or to imagine themselves as a serial killer.
ETA: If this is the incorrect circle, please let me know. I wasn't sure where this fit in.
Looking at the first link, Amazon lists the "reading age" as 18+
So, it seems to me, this book should not have been given to the 16 year old high school students. If they wanted to use the same author/publisher, they should have used the younger version that you linked.
I wouldn't even want it in a college writing class.