I don't want to jailbreak my friends 3ds
Why don't you want to jailbreak it?
He know that I love hacking things and try to do as much as possible on mine. But I don't want to bother with his
You should help your friend when you say you will. But you shouldn't do illegal things like jailbreak your 3DS. You could get into trouble.
I won't get in trouble. Jailbreaking consoles is not illegal.
Even if it is not illegal, you could still damage the device so you shouldn't mess with it. It will also void the warranty to mess with it.