How Do I twin cheats?

I agree. Someone resurrected an old, old, old thread, and things had changed in a major way since then. I'm going to close the thread to stop that sort of thing. The answer to the PreOFB twins is that there is no way to increase the likelihood without a mod for it. The answer if the person has OFB or later is that eating Cheesecake will increase the likelihood but the cheat "force twins" works for sure.