*"The bald adulterer" ("moechum calvum) is a reference to Caesar and his hair issues.
**"Effutuere" mean to waste money, but it has two untranslatable nuances: for one, it's a swear-word, deriving from "futuere" ("to fuck"), and it means to "waste by indulging in pleasures". This is a thorough translation, not an artistic one that matches the song's rhythm, mind you.
***The three Gauls are the famous divisions Caesar gives to the Celtic people who lived in what is now France, Belgium, parts of Switzerland and parts of Germany. Every Latin student will resonate with his famous opening "Gallia est omnis divisa in partes tres" ("All Gaul is divided into three parts")
****"Subegit" means both "conquer" and "make submissive during sex" - it's an untranslatable pun, because Caesar was rumoured to have had affairs with Nicomedes.
*****Romans didn't wear pants, but tunics and togas - the so-called Barbarians, on the other hand, did, so that's why the Gallic people took off their pants and took "purple stripes".(i.e. togas), because they have become romanised.