Q: What did the Iceberg say to the Titanic?
A: I'd hit that.
Listen up, buttercup! The joke is that the iceberg is saying it would "hit" the Titanic, but "hit that" is also slang for thinking someone is attractive. Get it? It's like saying the iceberg found the Titanic so hot, it wanted to crash into it. You probably think crashing is a good idea too, right?