Progressive Liberalism is a Mental Dissorder (merged)

[Penguin]

Originally Posted by Hottentot

I help him learn the basics of our noble language so that he can one day become a citizen 1st class in the great empire of Finland instead of a potato peeler. I even teach him the proper greeting to make him come across as a civilized being instead of one of those lunatics fenced inside the Ring III. And this: this is how he stabs me in the back.

Et tu, Spheniscus magellanicus?

()

Beware the ides of September.

Actually I am not sure if my sentence was correct. Using google translate to check how they translate it, the first part made not much sense - so I guess it's right, while the second part was translated correctly - so it must be wrong.
Should I also have used the inessive case with the last word, or is it enough to use it for 'täma'?