What do you think of this plan? I'm going to blackmail my crush into paying me money, but I'm just going to take his money and continue blackmailing him.
That's a horrible thing to do! Why would you blackmail someone you like?
I like money!
I can't even see anything redeemable about what you just said. You're taking advantage of him and its wrong to do that to anyone for any reason. On top of that if he's your crush I'm sure he's never going to want to speak to you again afterwards.
So what if I never talk to him again? I got what I wanted, and I got easy money in the process.
This is an extremely selfish attitude and a horrible thing to do someone. Blackmailing him will make him miserable, and he can even press charges against you if he wants. You need to not take advantage of people like this and instead be nicer to people.