b12 wont do anything for your aggression.... you're not going to find many things that are legal to up your aggression. And since there's no such thing as roid rage, you're not goign to find anything illegal to piss you off, its all a myth. Cheque drops would perhaps do it, but they're difficult to find, highly illegal and pretty dangerous. You're better off psyching yourself up.
yes or you could try cutting off the circulation to your testicles for around fifyeen minutes before your game, they should turn black and blue and that alone should make you pissed.