NO WHACKING!! It is abuse. Yes, it is. I'm sorry honey but when someone takes advantage of you like that, forces you to do things with threats, it's abuse. Of course you did it, you were threatened. What a hard, hard revelation. But maybe having this knowledge resurface will help you to better understand a lot of other things. You could say "if only" or "If I would have" or "If I wouldn't have" until the day you die and it won't change anything. You did what you had to do to survive. From what I've heard, you had every reason to believe your twin would carry out the threat. There is no reason at all to feel stupid--you didn't "let" this happen to you; those other kids knew it was bad and wrong, that's why they threatened you. They knew they could scare you into not telling. That's what abusers do. NO WHACKING