How about
pone caput suum in porcem
In an old article in Mad, a passage mentioned “Buggus Bunnius, the famous [for what?] Latin scholar,” is quoted as saying, “Stratus winnus; lorbrakus losus; paisus stratus shutus!” Which supposedly means (in *what language, *may I ask?) “Straight shooters always win, lawbreakers always lose, so it pays to shoot straight!”
What I would like to know is the correct Latin translation of the phrase, *not *the one Mr. “Bunnius” rendered.
How about this:
Qui recta et vera loquatur, semper vincit;
qui contra legem committat, semper vincitur;
ita recta et vera loqui lucratur.
Gratias multas. Vae victis. 
My favorite Latin malediction has been Ī in orcī ānum (go into the asshole of Orcus), though in attempting to find the source, I find that I must have corrupted it from this one from Erasmus: In orcī cūlum incidās (may you fall in the asshole of Orcus). Probably my version got confounded with Ī in malam crucem (go get crucified).
How about "Pigi Latinus? Insertus cranum et porcus baconsorucei. Oinkus! :eek:
Maybe not…
That should be “Latina porcorum”. Or “atinaLay orcorumpay”, if you prefer.