First, I'm not at all against NTSB reports. They serve an important function in allowing us to know (OK, it's mostly making educated guesses) how pilots got themselves into trouble. Every student could benefit from this knowledge. But I think the knowledge could be dispensed in a more meaningful and perhaps less harmful way.
That's why I suggest that you read a lesson-appropriate NTSB accident report before or after a lesson, and discuss it with your student. When students read these reports on their own, they're left to draw their own conclusions, many of which might be completely wrong. Why? Because NTSB reports can't and don't offer insight into what was happening in the pilot's mind before the accident.
After all, what does the phrase "failed to maintain sufficient flying speed" tell you about what the pilot was thinking before he stalled? As the CFI, you have enough common sense, insight, and experience to make an inference about what wheels were turning (or in desperate need of grease) in the pilot's mind before he or she bent an airplane.
This presentation-discussion method is sure to make NTSB reports more meaningful to your students. It's also more likely to keep your student's imagination from running wild about why a pilot crashed an airplane. After all, it's best not to scare our students, especially since cockpits don't have blankets under which they can crawl.