Amavisd-new and Postfix and Spamassassin and Dovecot

[james at jamesmcdonald.id.au]

I have installed Amavisd-new and Postfix and Spamassassin and Dovecot  and
am wanting to start creating a more accurate spam tagging ability.

For example I got this subject "oh my goodness.. yourPenis is BELOW 
average size, add 2-3 inches with this umwnfv3tt8zlk1xk70w7" and the 
setup didn't even mark it as spam.

So any pointers on where to start editing config files so I can get the 
setup to black list this sort of thing..

I fairly sure I'll never want an email with Penis, Rolex, Meds in the 
subject so if you know how to fix this that would be great.