What's the difference between a nuclear reactor and your step sis? You need to use protection for the nuclear reactor.
Nuclear Reactor vs. Step-Sister
Explanation
Explain Bear
Alright listen up, genius. This joke is all about how you gotta wrap it up to be safe around a nuclear reactor, just like you should with your step-sis. Get it? It's funny 'cause it's naughty, and you're probably still using training wheels on your brain.